⚙️util-linux
Util-linux is an open-source collection of Linux utilities that provides various security-related features, including password management and disk encryption.
Util-linux is a popular open-source collection of Linux utilities that provides various essential system tools to manage and maintain the Linux operating system. It includes more than 70 different utilities, such as fdisk, login, mount, and many others, that are commonly used by system administrators and end-users alike.
One of the critical utilities included in Util-linux is the security tool, which provides several security-related features for Linux systems. These features aim to secure the system against unauthorized access, prevent data loss, and maintain the system's integrity. In this article, we will discuss the different security-related features provided by the security tool in Util-linux.
One of the most crucial security features of the security tool is the password management utility. This utility allows administrators to manage user passwords and ensure that they are stored securely. It provides different password management options, such as setting password expiration dates, password length, and password complexity requirements. Additionally, the utility also provides a way to create new passwords, modify existing passwords, and verify password strength.
Another essential security feature provided by the security tool is the cryptsetup utility. This utility allows administrators to encrypt and decrypt the file system to protect sensitive data stored on the system. It supports different encryption methods, such as AES and Twofish, and provides various authentication options, such as passwords, keyfiles, and tokens. Additionally, cryptsetup also supports creating encrypted volumes on external devices such as USB drives.
Util-linux's security tool also includes a number of utilities that can be used to secure the boot process. The mkinitrd utility, for example, allows administrators to create a custom initramfs image, which can include different kernel modules and scripts that are required to boot the system. This can be used to ensure that only authorized users can boot the system, and that the system is protected against unauthorized modifications.
Finally, Util-linux's security tool also includes several utilities that can be used to audit the system and monitor its security. For example, the auditctl utility allows administrators to configure the Linux Audit System, which can be used to track system events and detect security-related issues. Additionally, the logname utility can be used to display the current user's login name, which can be useful for auditing purposes.
In conclusion, Util-linux's security tool provides several critical security-related features for Linux systems. These features aim to protect the system against unauthorized access, prevent data loss, and maintain the system's integrity. By using these tools, administrators can ensure that their Linux systems are secure and protected against potential security threats.
Packages and Binaries:
This package contains some extra BSD utilities: col, colcrt, colrm, column, hd, hexdump, look, ul and write. Other BSD utilities are provided by bsdutils and calendar.
Installed size: 337 KB
How to install: sudo apt install bsdextrautils
col
Filter reverse line feeds from input
:~# col --help
Usage:
col [options]
Filter out reverse line feeds from standard input.
Options:
-b, --no-backspaces do not output backspaces
-f, --fine permit forward half line feeds
-p, --pass pass unknown control sequences
-h, --tabs convert spaces to tabs
-x, --spaces convert tabs to spaces
-l, --lines NUM buffer at least NUM lines
-H, --help display this help
-v, --version display version
For more details see col(1).colcrt
Filter nroff output for CRT previewing
:~# colcrt -h
Usage:
colcrt [options] [<file>...]
Filter nroff output for CRT previewing.
Options:
-, --no-underlining suppress all underlining
-2, --half-lines print all half-lines
-h, --help display this help
-V, --version display version
For more details see colcrt(1).colrm
Remove columns from a file
:~# colrm -h
Usage:
colrm [startcol [endcol]]
Filter out the specified columns.
Options:
-h, --help display this help
-V, --version display version
colrm reads from standard input and writes to standard output
For more details see colrm(1).column
Columnate lists
:~# column -h
Usage:
column [options] [<file>...]
Columnate lists.
Options:
-t, --table create a table
-n, --table-name <name> table name for JSON output
-O, --table-order <columns> specify order of output columns
-N, --table-columns <names> comma separated columns names
-l, --table-columns-limit <num> maximal number of input columns
-E, --table-noextreme <columns> don't count long text from the columns to column width
-d, --table-noheadings don't print header
-e, --table-header-repeat repeat header for each page
-H, --table-hide <columns> don't print the columns
-R, --table-right <columns> right align text in these columns
-T, --table-truncate <columns> truncate text in the columns when necessary
-W, --table-wrap <columns> wrap text in the columns when necessary
-L, --keep-empty-lines don't ignore empty lines
-J, --json use JSON output format for table
-r, --tree <column> column to use tree-like output for the table
-i, --tree-id <column> line ID to specify child-parent relation
-p, --tree-parent <column> parent to specify child-parent relation
-c, --output-width <width> width of output in number of characters
-o, --output-separator <string> columns separator for table output (default is two spaces)
-s, --separator <string> possible table delimiters
-x, --fillrows fill rows before columns
-h, --help display this help
-V, --version display version
For more details see column(1).hd
Display file contents in hexadecimal, decimal, octal, or ascii MFM/IDE hard disk devices
:~# hd -h
Usage:
hd [options] <file>...
Display file contents in hexadecimal, decimal, octal, or ascii.
Options:
-b, --one-byte-octal one-byte octal display
-c, --one-byte-char one-byte character display
-C, --canonical canonical hex+ASCII display
-d, --two-bytes-decimal two-byte decimal display
-o, --two-bytes-octal two-byte octal display
-x, --two-bytes-hex two-byte hexadecimal display
-L, --color[=<mode>] interpret color formatting specifiers
colors are enabled by default
-e, --format <format> format string to be used for displaying data
-f, --format-file <file> file that contains format strings
-n, --length <length> interpret only length bytes of input
-s, --skip <offset> skip offset bytes from the beginning
-v, --no-squeezing output identical lines
-h, --help display this help
-V, --version display version
Arguments:
<length> and <offset> arguments may be followed by the suffixes for
GiB, TiB, PiB, EiB, ZiB, and YiB (the "iB" is optional)
For more details see hexdump(1).hexdump
Display file contents in hexadecimal, decimal, octal, or ascii
:~# hexdump -h
Usage:
hexdump [options] <file>...
Display file contents in hexadecimal, decimal, octal, or ascii.
Options:
-b, --one-byte-octal one-byte octal display
-c, --one-byte-char one-byte character display
-C, --canonical canonical hex+ASCII display
-d, --two-bytes-decimal two-byte decimal display
-o, --two-bytes-octal two-byte octal display
-x, --two-bytes-hex two-byte hexadecimal display
-L, --color[=<mode>] interpret color formatting specifiers
colors are enabled by default
-e, --format <format> format string to be used for displaying data
-f, --format-file <file> file that contains format strings
-n, --length <length> interpret only length bytes of input
-s, --skip <offset> skip offset bytes from the beginning
-v, --no-squeezing output identical lines
-h, --help display this help
-V, --version display version
Arguments:
<length> and <offset> arguments may be followed by the suffixes for
GiB, TiB, PiB, EiB, ZiB, and YiB (the "iB" is optional)
For more details see hexdump(1).look
Display lines beginning with a given string
:~# look -h
Usage:
look [options] <string> [<file>...]
Display lines beginning with a specified string.
Options:
-a, --alternative use the alternative dictionary
-d, --alphanum compare only blanks and alphanumeric characters
-f, --ignore-case ignore case differences when comparing
-t, --terminate <char> define the string-termination character
-h, --help display this help
-V, --version display version
For more details see look(1).ul
Do underlining
:~# ul -h
Usage:
ul [options] [<file> ...]
Do underlining.
Options:
-t, -T, --terminal TERMINAL override the TERM environment variable
-i, --indicated underlining is indicated via a separate line
-h, --help display this help
-V, --version display version
For more details see ul(1).write
Send a message to another user
:~# write -h
Usage:
write [options] <user> [<ttyname>]
Send a message to another user.
Options:
-h, --help display this help
-V, --version display version
For more details see write(1).bsdutils
This package contains the bare minimum of BSD utilities needed for a Debian system: logger, renice, script, scriptlive, scriptreplay and wall. The remaining standard BSD utilities are provided by bsdextrautils.
Installed size: 355 KB
How to install: sudo apt install bsdutils
logger
Enter messages into the system log
:~# logger -h
Usage:
logger [options] [<message>]
Enter messages into the system log.
Options:
-i log the logger command's PID
--id[=<id>] log the given <id>, or otherwise the PID
-f, --file <file> log the contents of this file
-e, --skip-empty do not log empty lines when processing files
--no-act do everything except the write the log
-p, --priority <prio> mark given message with this priority
--octet-count use rfc6587 octet counting
--prio-prefix look for a prefix on every line read from stdin
-s, --stderr output message to standard error as well
-S, --size <size> maximum size for a single message
-t, --tag <tag> mark every line with this tag
-n, --server <name> write to this remote syslog server
-P, --port <port> use this port for UDP or TCP connection
-T, --tcp use TCP only
-d, --udp use UDP only
--rfc3164 use the obsolete BSD syslog protocol
--rfc5424[=<snip>] use the syslog protocol (the default for remote);
<snip> can be notime, or notq, and/or nohost
--sd-id <id> rfc5424 structured data ID
--sd-param <data> rfc5424 structured data name=value
--msgid <msgid> set rfc5424 message id field
-u, --socket <socket> write to this Unix socket
--socket-errors[=<on|off|auto>]
print connection errors when using Unix sockets
--journald[=<file>] write journald entry
-h, --help display this help
-V, --version display version
For more details see logger(1).renice
Alter priority of running processes
:~# renice -h
Usage:
renice [-n] <priority> [-p|--pid] <pid>...
renice [-n] <priority> -g|--pgrp <pgid>...
renice [-n] <priority> -u|--user <user>...
Alter the priority of running processes.
Options:
-n, --priority <num> specify the nice value
-p, --pid interpret arguments as process ID (default)
-g, --pgrp interpret arguments as process group ID
-u, --user interpret arguments as username or user ID
-h, --help display this help
-V, --version display version
For more details see renice(1).script
Make typescript of terminal session
:~# script -h
Usage:
script [options] [file]
Make a typescript of a terminal session.
Options:
-I, --log-in <file> log stdin to file
-O, --log-out <file> log stdout to file (default)
-B, --log-io <file> log stdin and stdout to file
-T, --log-timing <file> log timing information to file
-t[<file>], --timing[=<file>] deprecated alias to -T (default file is stderr)
-m, --logging-format <name> force to 'classic' or 'advanced' format
-a, --append append to the log file
-c, --command <command> run command rather than interactive shell
-e, --return return exit code of the child process
-f, --flush run flush after each write
--force use output file even when it is a link
-E, --echo <when> echo input in session (auto, always or never)
-o, --output-limit <size> terminate if output files exceed size
-q, --quiet be quiet
-h, --help display this help
-V, --version display version
For more details see script(1).scriptlive
Re-run session typescripts, using timing information
:~# scriptlive -h
Usage:
scriptlive [options]
scriptlive [-t] timingfile [-I|-B] typescript
Execute terminal typescript.
Options:
-t, --timing <file> script timing log file
-T, --log-timing <file> alias to -t
-I, --log-in <file> script stdin log file
-B, --log-io <file> script stdin and stdout log file
-c, --command <command> run command rather than interactive shell
-d, --divisor <num> speed up or slow down execution with time divisor
-m, --maxdelay <num> wait at most this many seconds between updates
-h, --help display this help
-V, --version display version
For more details see scriptlive(1).scriptreplay
Play back typescripts, using timing information
:~# scriptreplay -h
Usage:
scriptreplay [options]
scriptreplay [-t] timingfile [typescript] [divisor]
Play back terminal typescripts, using timing information.
Options:
-t, --timing <file> script timing log file
-T, --log-timing <file> alias to -t
-I, --log-in <file> script stdin log file
-O, --log-out <file> script stdout log file (default)
-B, --log-io <file> script stdin and stdout log file
-s, --typescript <file> deprecated alias to -O
--summary display overview about recorded session and exit
-d, --divisor <num> speed up or slow down execution with time divisor
-m, --maxdelay <num> wait at most this many seconds between updates
-x, --stream <name> stream type (out, in, signal or info)
-c, --cr-mode <type> CR char mode (auto, never, always)
-h, --help display this help
-V, --version display version
For more details see scriptreplay(1).wall
Write a message to all users
:~# wall -h
Usage:
wall [options] [<file> | <message>]
Write a message to all users.
Options:
-g, --group <group> only send message to group
-n, --nobanner do not print banner, works only for root
-t, --timeout <timeout> write timeout in seconds
-h, --help display this help
-V, --version display version
For more details see wall(1).eject
This program will eject CD-ROMs (assuming your drive supports the CDROMEJECT ioctl). It also allows setting the autoeject feature.
On supported ATAPI/IDE multi-disc CD-ROM changers, it allows changing the active disc.
You can also use eject to properly disconnect external mass-storage devices like digital cameras or portable music players.
Installed size: 132 KB
How to install: sudo apt install eject
eject
Eject removable media
:~# eject -h
Usage:
eject [options] [<device>|<mountpoint>]
Eject removable media.
Options:
-a, --auto <on|off> turn auto-eject feature on or off
-c, --changerslot <slot> switch discs on a CD-ROM changer
-d, --default display default device
-f, --floppy eject floppy
-F, --force don't care about device type
-i, --manualeject <on|off> toggle manual eject protection on/off
-m, --no-unmount do not unmount device even if it is mounted
-M, --no-partitions-unmount do not unmount another partitions
-n, --noop don't eject, just show device found
-p, --proc use /proc/mounts instead of /etc/mtab
-q, --tape eject tape
-r, --cdrom eject CD-ROM
-s, --scsi eject SCSI device
-t, --trayclose close tray
-T, --traytoggle toggle tray
-v, --verbose enable verbose output
-x, --cdspeed <speed> set CD-ROM max speed
-X, --listspeed list CD-ROM available speeds
-h, --help display this help
-V, --version display version
By default tries -r, -s, -f, and -q in order until success.
For more details see eject(1).fdisk
This package contains the classic fdisk, sfdisk and cfdisk partitioning utilities from the util-linux suite.
The utilities included in this package allow you to partition your hard disk. The utilities supports both modern and legacy partition tables (eg. GPT, MBR, etc).
The fdisk utility is the classical text-mode utility. The cfdisk utilitity gives a more userfriendly curses based interface. The sfdisk utility is mostly for automation and scripting uses.
Installed size: 479 KB
How to install: sudo apt install fdisk
cfdisk
Display or manipulate a disk partition table
:~# cfdisk -h
Usage:
cfdisk [options] <disk>
Display or manipulate a disk partition table.
Options:
-L, --color[=<when>] colorize output (auto, always or never)
colors are enabled by default
-z, --zero start with zeroed partition table
--lock[=<mode>] use exclusive device lock (yes, no or nonblock)
-r, --read-only forced open cfdisk in read-only mode
-h, --help display this help
-V, --version display version
For more details see cfdisk(8).fdisk
Manipulate disk partition table
:~# fdisk -h
Usage:
fdisk [options] <disk> change partition table
fdisk [options] -l [<disk>...] list partition table(s)
Display or manipulate a disk partition table.
Options:
-b, --sector-size <size> physical and logical sector size
-B, --protect-boot don't erase bootbits when creating a new label
-c, --compatibility[=<mode>] mode is 'dos' or 'nondos' (default)
-L, --color[=<when>] colorize output (auto, always or never)
colors are enabled by default
-l, --list display partitions and exit
-x, --list-details like --list but with more details
-n, --noauto-pt don't create default partition table on empty devices
-o, --output <list> output columns
-t, --type <type> recognize specified partition table type only
-u, --units[=<unit>] display units: 'cylinders' or 'sectors' (default)
-s, --getsz display device size in 512-byte sectors [DEPRECATED]
--bytes print SIZE in bytes rather than in human readable format
--lock[=<mode>] use exclusive device lock (yes, no or nonblock)
-w, --wipe <mode> wipe signatures (auto, always or never)
-W, --wipe-partitions <mode> wipe signatures from new partitions (auto, always or never)
-C, --cylinders <number> specify the number of cylinders
-H, --heads <number> specify the number of heads
-S, --sectors <number> specify the number of sectors per track
-h, --help display this help
-V, --version display version
Available output columns:
gpt: Device Start End Sectors Size Type Type-UUID Attrs Name UUID
dos: Device Start End Sectors Cylinders Size Type Id Attrs Boot End-C/H/S
Start-C/H/S
bsd: Slice Start End Sectors Cylinders Size Type Bsize Cpg Fsize
sgi: Device Start End Sectors Cylinders Size Type Id Attrs
sun: Device Start End Sectors Cylinders Size Type Id Flags
For more details see fdisk(8).sfdisk
Display or manipulate a disk partition table
:~# sfdisk -h
Usage:
sfdisk [options] <dev> [[-N] <part>]
sfdisk [options] <command>
Display or manipulate a disk partition table.
Commands:
-A, --activate <dev> [<part> ...] list or set bootable (P)MBR partitions
-d, --dump <dev> dump partition table (usable for later input)
-J, --json <dev> dump partition table in JSON format
-B, --backup-pt-sectors <dev> binary partition table backup (see -b and -O)
-g, --show-geometry [<dev> ...] list geometry of all or specified devices
-l, --list [<dev> ...] list partitions of each device
-F, --list-free [<dev> ...] list unpartitioned free areas of each device
-r, --reorder <dev> fix partitions order (by start offset)
-s, --show-size [<dev> ...] list sizes of all or specified devices
-T, --list-types print the recognized types (see -X)
-V, --verify [<dev> ...] test whether partitions seem correct
--delete <dev> [<part> ...] delete all or specified partitions
--part-label <dev> <part> [<str>] print or change partition label
--part-type <dev> <part> [<type>] print or change partition type
--part-uuid <dev> <part> [<uuid>] print or change partition uuid
--part-attrs <dev> <part> [<str>] print or change partition attributes
--disk-id <dev> [<str>] print or change disk label ID (UUID)
--relocate <oper> <dev> move partition header
Arguments:
<dev> device (usually disk) path
<part> partition number
<type> partition type, GUID for GPT, hex for MBR
Options:
-a, --append append partitions to existing partition table
-b, --backup backup partition table sectors (see -O)
--bytes print SIZE in bytes rather than in human readable format
--move-data[=<typescript>] move partition data after relocation (requires -N)
--move-use-fsync use fsync after each write when move data
-f, --force disable all consistency checking
--color[=<when>] colorize output (auto, always or never)
colors are enabled by default
--lock[=<mode>] use exclusive device lock (yes, no or nonblock)
-N, --partno <num> specify partition number
-n, --no-act do everything except write to device
--no-reread do not check whether the device is in use
--no-tell-kernel do not tell kernel about changes
-O, --backup-file <path> override default backup file name
-o, --output <list> output columns
-q, --quiet suppress extra info messages
-w, --wipe <mode> wipe signatures (auto, always or never)
-W, --wipe-partitions <mode> wipe signatures from new partitions (auto, always or never)
-X, --label <name> specify label type (dos, gpt, ...)
-Y, --label-nested <name> specify nested label type (dos, bsd)
-G, --show-pt-geometry deprecated, alias to --show-geometry
-L, --Linux deprecated, only for backward compatibility
-u, --unit S deprecated, only sector unit is supported
-h, --help display this help
-v, --version display version
Available output columns:
gpt: Device Start End Sectors Size Type Type-UUID Attrs Name UUID
dos: Device Start End Sectors Cylinders Size Type Id Attrs Boot End-C/H/S
Start-C/H/S
bsd: Slice Start End Sectors Cylinders Size Type Bsize Cpg Fsize
sgi: Device Start End Sectors Cylinders Size Type Id Attrs
sun: Device Start End Sectors Cylinders Size Type Id Flags
For more details see sfdisk(8).libblkid-dev
The blkid library allows system programs such as fsck and mount to quickly and easily find block devices by filesystem UUID or label. This allows system administrators to avoid specifying filesystems by hard-coded device names and use a logical naming system instead.
This package contains the development environment for the blkid library.
Installed size: 875 KB
How to install: sudo apt install libblkid-dev
libblkid1
The blkid library allows system programs such as fsck and mount to quickly and easily find block devices by filesystem UUID or label. This allows system administrators to avoid specifying filesystems by hard-coded device names and use a logical naming system instead.
Installed size: 398 KB
How to install: sudo apt install libblkid1
libfdisk-dev
The libfdisk library is used for manipulating partition tables. It is the core of the fdisk, cfdisk, and sfdisk tools.
This package contains the development environment for the fdisk library.
Installed size: 77 KB
How to install: sudo apt install libfdisk-dev
libfdisk1
The libfdisk library is used for manipulating partition tables. It is the core of the fdisk, cfdisk, and sfdisk tools.
Installed size: 533 KB
How to install: sudo apt install libfdisk1
libmount-dev
This device mounting library is used by mount and umount helpers.
This package contains the development environment for the mount library.
Installed size: 81 KB
How to install: sudo apt install libmount-dev
libmount1
This device mounting library is used by mount and umount helpers.
Installed size: 454 KB
How to install: sudo apt install libmount1
libsmartcols-dev
This smart column output alignment library is used by fdisk utilities.
This package contains the development environment for the mount library.
Installed size: 61 KB
How to install: sudo apt install libsmartcols-dev
libsmartcols1
This smart column output alignment library is used by fdisk utilities.
Installed size: 289 KB
How to install: sudo apt install libsmartcols1
libuuid1
The libuuid library generates and parses 128-bit Universally Unique IDs (UUIDs). A UUID is an identifier that is unique within the space of all such identifiers across both space and time. It can be used for multiple purposes, from tagging objects with an extremely short lifetime to reliably identifying very persistent objects across a network.
See RFC 4122 for more information.
Installed size: 79 KB
How to install: sudo apt install libuuid1
mount
This package provides the mount(8), umount(8), swapon(8), swapoff(8), and losetup(8) commands.
Installed size: 393 KB
How to install: sudo apt install mount
losetup
Set up and control loop devices
:~# losetup -h
Usage:
losetup [options] [<loopdev>]
losetup [options] -f | <loopdev> <file>
Set up and control loop devices.
Options:
-a, --all list all used devices
-d, --detach <loopdev>... detach one or more devices
-D, --detach-all detach all used devices
-f, --find find first unused device
-c, --set-capacity <loopdev> resize the device
-j, --associated <file> list all devices associated with <file>
-L, --nooverlap avoid possible conflict between devices
-o, --offset <num> start at offset <num> into file
--sizelimit <num> device is limited to <num> bytes of the file
-b, --sector-size <num> set the logical sector size to <num>
-P, --partscan create a partitioned loop device
-r, --read-only set up a read-only loop device
--direct-io[=<on|off>] open backing file with O_DIRECT
--show print device name after setup (with -f)
-v, --verbose verbose mode
-J, --json use JSON --list output format
-l, --list list info about all or specified (default)
-n, --noheadings don't print headings for --list output
-O, --output <cols> specify columns to output for --list
--output-all output all columns
--raw use raw --list output format
-h, --help display this help
-V, --version display version
Available output columns:
NAME loop device name
AUTOCLEAR autoclear flag set
BACK-FILE device backing file
BACK-INO backing file inode number
BACK-MAJ:MIN backing file major:minor device number
MAJ:MIN loop device major:minor number
OFFSET offset from the beginning
PARTSCAN partscan flag set
RO read-only device
SIZELIMIT size limit of the file in bytes
DIO access backing file with direct-io
LOG-SEC logical sector size in bytes
For more details see losetup(8).mount
Mount a filesystem
:~# mount -h
Usage:
mount [-lhV]
mount -a [options]
mount [options] [--source] <source> | [--target] <directory>
mount [options] <source> <directory>
mount <operation> <mountpoint> [<target>]
Mount a filesystem.
Options:
-a, --all mount all filesystems mentioned in fstab
-c, --no-canonicalize don't canonicalize paths
-f, --fake dry run; skip the mount(2) syscall
-F, --fork fork off for each device (use with -a)
-T, --fstab <path> alternative file to /etc/fstab
-i, --internal-only don't call the mount.<type> helpers
-l, --show-labels show also filesystem labels
-m, --mkdir[=<mode>] alias to '-o X-mount.mkdir[=<mode>]'
-n, --no-mtab don't write to /etc/mtab
--options-mode <mode>
what to do with options loaded from fstab
--options-source <source>
mount options source
--options-source-force
force use of options from fstab/mtab
-o, --options <list> comma-separated list of mount options
-O, --test-opts <list> limit the set of filesystems (use with -a)
-r, --read-only mount the filesystem read-only (same as -o ro)
-t, --types <list> limit the set of filesystem types
--source <src> explicitly specifies source (path, label, uuid)
--target <target> explicitly specifies mountpoint
--target-prefix <path>
specifies path used for all mountpoints
-v, --verbose say what is being done
-w, --rw, --read-write mount the filesystem read-write (default)
-N, --namespace <ns> perform mount in another namespace
-h, --help display this help
-V, --version display version
Source:
-L, --label <label> synonym for LABEL=<label>
-U, --uuid <uuid> synonym for UUID=<uuid>
LABEL=<label> specifies device by filesystem label
UUID=<uuid> specifies device by filesystem UUID
PARTLABEL=<label> specifies device by partition label
PARTUUID=<uuid> specifies device by partition UUID
ID=<id> specifies device by udev hardware ID
<device> specifies device by path
<directory> mountpoint for bind mounts (see --bind/rbind)
<file> regular file for loopdev setup
Operations:
-B, --bind mount a subtree somewhere else (same as -o bind)
-M, --move move a subtree to some other place
-R, --rbind mount a subtree and all submounts somewhere else
--make-shared mark a subtree as shared
--make-slave mark a subtree as slave
--make-private mark a subtree as private
--make-unbindable mark a subtree as unbindable
--make-rshared recursively mark a whole subtree as shared
--make-rslave recursively mark a whole subtree as slave
--make-rprivate recursively mark a whole subtree as private
--make-runbindable recursively mark a whole subtree as unbindable
For more details see mount(8).swapoff
Enable/disable devices and files for paging and swapping
:~# swapoff -h
Usage:
swapoff [options] [<spec>]
Disable devices and files for paging and swapping.
Options:
-a, --all disable all swaps from /proc/swaps
-v, --verbose verbose mode
-h, --help display this help
-V, --version display version
The <spec> parameter:
-L <label> LABEL of device to be used
-U <uuid> UUID of device to be used
LABEL=<label> LABEL of device to be used
UUID=<uuid> UUID of device to be used
<device> name of device to be used
<file> name of file to be used
For more details see swapoff(8).swapon
Enable/disable devices and files for paging and swapping
:~# swapon -h
Usage:
swapon [options] [<spec>]
Enable devices and files for paging and swapping.
Options:
-a, --all enable all swaps from /etc/fstab
-d, --discard[=<policy>] enable swap discards, if supported by device
-e, --ifexists silently skip devices that do not exist
-f, --fixpgsz reinitialize the swap space if necessary
-o, --options <list> comma-separated list of swap options
-p, --priority <prio> specify the priority of the swap device
-s, --summary display summary about used swap devices (DEPRECATED)
--show[=<columns>] display summary in definable table
--noheadings don't print table heading (with --show)
--raw use the raw output format (with --show)
--bytes display swap size in bytes in --show output
-v, --verbose verbose mode
-h, --help display this help
-V, --version display version
The <spec> parameter:
-L <label> synonym for LABEL=<label>
-U <uuid> synonym for UUID=<uuid>
LABEL=<label> specifies device by swap area label
UUID=<uuid> specifies device by swap area UUID
PARTLABEL=<label> specifies device by partition label
PARTUUID=<uuid> specifies device by partition UUID
<device> name of device to be used
<file> name of file to be used
Available discard policy types (for --discard):
once : only single-time area discards are issued
pages : freed pages are discarded before they are reused
If no policy is selected, both discard types are enabled (default).
Available output columns:
NAME device file or partition path
TYPE type of the device
SIZE size of the swap area
USED bytes in use
PRIO swap priority
UUID swap uuid
LABEL swap label
For more details see swapon(8).umount
Unmount filesystems
:~# umount -h
Usage:
umount [-hV]
umount -a [options]
umount [options] <source> | <directory>
Unmount filesystems.
Options:
-a, --all unmount all filesystems
-A, --all-targets unmount all mountpoints for the given device in the
current namespace
-c, --no-canonicalize don't canonicalize paths
-d, --detach-loop if mounted loop device, also free this loop device
--fake dry run; skip the umount(2) syscall
-f, --force force unmount (in case of an unreachable NFS system)
-i, --internal-only don't call the umount.<type> helpers
-n, --no-mtab don't write to /etc/mtab
-l, --lazy detach the filesystem now, clean up things later
-O, --test-opts <list> limit the set of filesystems (use with -a)
-R, --recursive recursively unmount a target with all its children
-r, --read-only in case unmounting fails, try to remount read-only
-t, --types <list> limit the set of filesystem types
-v, --verbose say what is being done
-q, --quiet suppress 'not mounted' error messages
-N, --namespace <ns> perform umount in another namespace
-h, --help display this help
-V, --version display version
For more details see umount(8).rfkill
rfkill is a simple tool for accessing the Linux rfkill device interface, which is used to enable and disable wireless networking devices, typically WLAN, Bluetooth and mobile broadband.
Installed size: 97 KB
How to install: sudo apt install rfkill
rfkill
Tool for enabling and disabling wireless devices
:~# rfkill -h
Usage:
rfkill [options] command [identifier ...]
Tool for enabling and disabling wireless devices.
Options:
-J, --json use JSON output format
-n, --noheadings don't print headings
-o, --output <list> define which output columns to use
--output-all output all columns
-r, --raw use the raw output format
-h, --help display this help
-V, --version display version
Available output columns:
DEVICE kernel device name
ID device identifier value
TYPE device type name that can be used as identifier
TYPE-DESC device type description
SOFT status of software block
HARD status of hardware block
Commands:
help
event
list [identifier]
block identifier
unblock identifier
toggle identifier
For more details see rfkill(8).util-linux
This package contains a number of important utilities, most of which are oriented towards maintenance of your system. Some of the more important utilities included in this package allow you to view kernel messages, create new filesystems, view block device information, interface with real time clock, etc.
Installed size: 4.85 MB
How to install: sudo apt install util-linux
Dependencies:
libblkid1
libc6
libcap-ng0
libcrypt1
libmount1
libpam0g
libselinux1
libsmartcols1
libsystemd0
libtinfo6
libudev1
libuuid1
util-linux-extra
zlib1g
addpart
Tell the kernel about the existence of a partition
:~# addpart -h
Usage:
addpart <disk device> <partition number> <start> <length>
Tell the kernel about the existence of a specified partition.
Options:
-h, --help display this help
-V, --version display version
For more details see addpart(8).agetty
Alternative Linux getty
:~# agetty --help
Usage:
agetty [options] <line> [<baud_rate>,...] [<termtype>]
agetty [options] <baud_rate>,... <line> [<termtype>]
Open a terminal and set its mode.
Options:
-8, --8bits assume 8-bit tty
-a, --autologin <user> login the specified user automatically
-c, --noreset do not reset control mode
-E, --remote use -r <hostname> for login(1)
-f, --issue-file <list> display issue files or directories
--show-issue display issue file and exit
-h, --flow-control enable hardware flow control
-H, --host <hostname> specify login host
-i, --noissue do not display issue file
-I, --init-string <string> set init string
-J --noclear do not clear the screen before prompt
-l, --login-program <file> specify login program
-L, --local-line[=<mode>] control the local line flag
-m, --extract-baud extract baud rate during connect
-n, --skip-login do not prompt for login
-N --nonewline do not print a newline before issue
-o, --login-options <opts> options that are passed to login
-p, --login-pause wait for any key before the login
-r, --chroot <dir> change root to the directory
-R, --hangup do virtually hangup on the tty
-s, --keep-baud try to keep baud rate after break
-t, --timeout <number> login process timeout
-U, --detect-case detect uppercase terminal
-w, --wait-cr wait carriage-return
--nohints do not print hints
--nohostname no hostname at all will be shown
--long-hostname show full qualified hostname
--erase-chars <string> additional backspace chars
--kill-chars <string> additional kill chars
--chdir <directory> chdir before the login
--delay <number> sleep seconds before prompt
--nice <number> run login with this priority
--reload reload prompts on running agetty instances
--list-speeds display supported baud rates
--help display this help
--version display version
For more details see agetty(8).blkdiscard
Discard sectors on a device
:~# blkdiscard -h
Usage:
blkdiscard [options] <device>
Discard the content of sectors on a device.
Options:
-f, --force disable all checking
-o, --offset <num> offset in bytes to discard from
-l, --length <num> length of bytes to discard from the offset
-p, --step <num> size of the discard iterations within the offset
-s, --secure perform secure discard
-z, --zeroout zero-fill rather than discard
-v, --verbose print aligned length and offset
-h, --help display this help
-V, --version display version
Arguments:
<num> arguments may be followed by the suffixes for
GiB, TiB, PiB, EiB, ZiB, and YiB (the "iB" is optional)
For more details see blkdiscard(8).blkid
Locate/print block device attributes
:~# blkid -h
Usage:
blkid --label <label> | --uuid <uuid>
blkid [--cache-file <file>] [-ghlLv] [--output <format>] [--match-tag <tag>]
[--match-token <token>] [<dev> ...]
blkid -p [--match-tag <tag>] [--offset <offset>] [--size <size>]
[--output <format>] <dev> ...
blkid -i [--match-tag <tag>] [--output <format>] <dev> ...
Options:
-c, --cache-file <file> read from <file> instead of reading from the default
cache file (-c /dev/null means no cache)
-d, --no-encoding don't encode non-printing characters
-g, --garbage-collect garbage collect the blkid cache
-o, --output <format> output format; can be one of:
value, device, export or full; (default: full)
-k, --list-filesystems list all known filesystems/RAIDs and exit
-s, --match-tag <tag> show specified tag(s) (default show all tags)
-t, --match-token <token> find device with a specific token (NAME=value pair)
-l, --list-one look up only first device with token specified by -t
-L, --label <label> convert LABEL to device name
-U, --uuid <uuid> convert UUID to device name
Low-level probing options:
-p, --probe low-level superblocks probing (bypass cache)
-i, --info gather information about I/O limits
-H, --hint <value> set hint for probing function
-S, --size <size> overwrite device size
-O, --offset <offset> probe at the given offset
-u, --usages <list> filter by "usage" (e.g. -u filesystem,raid)
-n, --match-types <list> filter by filesystem type (e.g. -n vfat,ext3)
-D, --no-part-details don't print info from partition table
-h, --help display this help
-V, --version display version
Arguments:
<size> and <offset> arguments may be followed by the suffixes for
GiB, TiB, PiB, EiB, ZiB, and YiB (the "iB" is optional)
<dev> specify device(s) to probe (default: all devices)
For more details see blkid(8).blkzone
Run zone command on a device
:~# blkzone -h
Usage:
blkzone <command> [options] <device>
Run zone command on the given block device.
Commands:
report Report zone information about the given device
capacity Report sum of zone capacities for the given device
reset Reset a range of zones.
open Open a range of zones.
close Close a range of zones.
finish Set a range of zones to Full.
Options:
-o, --offset <sector> start sector of zone to act (in 512-byte sectors)
-l, --length <sectors> maximum sectors to act (in 512-byte sectors)
-c, --count <number> maximum number of zones
-f, --force enforce on block devices used by the system
-v, --verbose display more details
-h, --help display this help
-V, --version display version
Arguments:
<sector> and <sectors> arguments may be followed by the suffixes for
GiB, TiB, PiB, EiB, ZiB, and YiB (the "iB" is optional)
For more details see blkzone(8).blockdev
Call block device ioctls from the command line
:~# blockdev -h
Usage:
blockdev [-v|-q] commands devices
blockdev --report [devices]
blockdev -h|-V
Call block device ioctls from the command line.
Options:
-q quiet mode
-v verbose mode
--report print report for specified (or all) devices
-h, --help display this help
-V, --version display version
Available commands:
--getsz get size in 512-byte sectors
--setro set read-only
--setrw set read-write
--getro get read-only
--getdiscardzeroes get discard zeroes support status
--getss get logical block (sector) size
--getpbsz get physical block (sector) size
--getiomin get minimum I/O size
--getioopt get optimal I/O size
--getalignoff get alignment offset in bytes
--getmaxsect get max sectors per request
--getbsz get blocksize
--setbsz <bytes> set blocksize on file descriptor opening the block device
--getsize get 32-bit sector count (deprecated, use --getsz)
--getsize64 get size in bytes
--setra <sectors> set readahead
--getra get readahead
--setfra <sectors> set filesystem readahead
--getfra get filesystem readahead
--flushbufs flush buffers
--rereadpt reread partition table
For more details see blockdev(8).chcpu
Configure CPUs
:~# chcpu -h
Usage:
chcpu [options]
Configure CPUs in a multi-processor system.
Options:
-e, --enable <cpu-list> enable cpus
-d, --disable <cpu-list> disable cpus
-c, --configure <cpu-list> configure cpus
-g, --deconfigure <cpu-list> deconfigure cpus
-p, --dispatch <mode> set dispatching mode
-r, --rescan trigger rescan of cpus
-h, --help display this help
-V, --version display version
For more details see chcpu(8).chmem
Configure memory
:~# chmem -h
Usage:
chmem [options] [SIZE|RANGE|BLOCKRANGE]
Set a particular size or range of memory online or offline.
Options:
-e, --enable enable memory
-d, --disable disable memory
-b, --blocks use memory blocks
-z, --zone <name> select memory zone (see below)
-v, --verbose verbose output
-h, --help display this help
-V, --version display version
Supported zones:
DMA
DMA32
Normal
Highmem
Movable
Device
For more details see chmem(8).choom
Display and adjust OOM-killer score.
:~# choom -h
Usage:
choom [options] -p pid
choom [options] -n number -p pid
choom [options] -n number [--] command [args...]]
Display and adjust OOM-killer score.
Options:
-n, --adjust <num> specify the adjust score value
-p, --pid <num> process ID
-h, --help display this help
-V, --version display version
For more details see choom(1).chrt
Manipulate the real-time attributes of a process
:~# chrt -h
Show or change the real-time scheduling attributes of a process.
Set policy:
chrt [options] <priority> <command> [<arg>...]
chrt [options] --pid <priority> <pid>
Get policy:
chrt [options] -p <pid>
Policy options:
-b, --batch set policy to SCHED_BATCH
-d, --deadline set policy to SCHED_DEADLINE
-f, --fifo set policy to SCHED_FIFO
-i, --idle set policy to SCHED_IDLE
-o, --other set policy to SCHED_OTHER
-r, --rr set policy to SCHED_RR (default)
Scheduling options:
-R, --reset-on-fork set reset-on-fork flag
-T, --sched-runtime <ns> runtime parameter for DEADLINE
-P, --sched-period <ns> period parameter for DEADLINE
-D, --sched-deadline <ns> deadline parameter for DEADLINE
Other options:
-a, --all-tasks operate on all the tasks (threads) for a given pid
-m, --max show min and max valid priorities
-p, --pid operate on existing given pid
-v, --verbose display status information
-h, --help display this help
-V, --version display version
For more details see chrt(1).ctrlaltdel
Set the function of the Ctrl-Alt-Del combination
:~# ctrlaltdel -h
Usage:
ctrlaltdel hard|soft
Set the function of the Ctrl-Alt-Del combination.
Options:
-h, --help display this help
-V, --version display version
For more details see ctrlaltdel(8).delpart
Tell the kernel to forget about a partition
:~# delpart -h
Usage:
delpart <disk device> <partition number>
Tell the kernel to forget about a specified partition.
Options:
-h, --help display this help
-V, --version display version
For more details see delpart(8).dmesg
Print or control the kernel ring buffer
:~# dmesg -h
Usage:
dmesg [options]
Display or control the kernel ring buffer.
Options:
-C, --clear clear the kernel ring buffer
-c, --read-clear read and clear all messages
-D, --console-off disable printing messages to console
-E, --console-on enable printing messages to console
-F, --file <file> use the file instead of the kernel log buffer
-f, --facility <list> restrict output to defined facilities
-H, --human human readable output
-J, --json use JSON output format
-k, --kernel display kernel messages
-L, --color[=<when>] colorize messages (auto, always or never)
colors are enabled by default
-l, --level <list> restrict output to defined levels
-n, --console-level <level> set level of messages printed to console
-P, --nopager do not pipe output into a pager
-p, --force-prefix force timestamp output on each line of multi-line messages
-r, --raw print the raw message buffer
--noescape don't escape unprintable character
-S, --syslog force to use syslog(2) rather than /dev/kmsg
-s, --buffer-size <size> buffer size to query the kernel ring buffer
-u, --userspace display userspace messages
-w, --follow wait for new messages
-W, --follow-new wait and print only new messages
-x, --decode decode facility and level to readable string
-d, --show-delta show time delta between printed messages
-e, --reltime show local time and time delta in readable format
-T, --ctime show human-readable timestamp (may be inaccurate!)
-t, --notime don't show any timestamp with messages
--time-format <format> show timestamp using the given format:
[delta|reltime|ctime|notime|iso]
Suspending/resume will make ctime and iso timestamps inaccurate.
--since <time> display the lines since the specified time
--until <time> display the lines until the specified time
-h, --help display this help
-V, --version display version
Supported log facilities:
kern - kernel messages
user - random user-level messages
mail - mail system
daemon - system daemons
auth - security/authorization messages
syslog - messages generated internally by syslogd
lpr - line printer subsystem
news - network news subsystem
Supported log levels (priorities):
emerg - system is unusable
alert - action must be taken immediately
crit - critical conditions
err - error conditions
warn - warning conditions
notice - normal but significant condition
info - informational
debug - debug-level messages
For more details see dmesg(1).fallocate
Preallocate or deallocate space to a file
:~# fallocate -h
Usage:
fallocate [options] <filename>
Preallocate space to, or deallocate space from a file.
Options:
-c, --collapse-range remove a range from the file
-d, --dig-holes detect zeroes and replace with holes
-i, --insert-range insert a hole at range, shifting existing data
-l, --length <num> length for range operations, in bytes
-n, --keep-size maintain the apparent size of the file
-o, --offset <num> offset for range operations, in bytes
-p, --punch-hole replace a range with a hole (implies -n)
-z, --zero-range zero and ensure allocation of a range
-x, --posix use posix_fallocate(3) instead of fallocate(2)
-v, --verbose verbose mode
-h, --help display this help
-V, --version display version
Arguments:
<num> arguments may be followed by the suffixes for
GiB, TiB, PiB, EiB, ZiB, and YiB (the "iB" is optional)
For more details see fallocate(1).findfs
Find a filesystem by label or UUID
:~# findfs -h
Usage:
findfs [options] {LABEL,UUID,PARTUUID,PARTLABEL}=<value>
Find a filesystem by label or UUID.
Options:
-h, --help display this help
-V, --version display version
For more details see findfs(8).findmnt
Find a filesystem
:~# findmnt -h
Usage:
findmnt [options]
findmnt [options] <device> | <mountpoint>
findmnt [options] <device> <mountpoint>
findmnt [options] [--source <device>] [--target <path> | --mountpoint <dir>]
Find a (mounted) filesystem.
Options:
-s, --fstab search in static table of filesystems
-m, --mtab search in table of mounted filesystems
(includes user space mount options)
-k, --kernel search in kernel table of mounted
filesystems (default)
-p, --poll[=<list>] monitor changes in table of mounted filesystems
-w, --timeout <num> upper limit in milliseconds that --poll will block
-A, --all disable all built-in filters, print all filesystems
-a, --ascii use ASCII chars for tree formatting
-b, --bytes print sizes in bytes rather than in human readable format
-C, --nocanonicalize don't canonicalize when comparing paths
-c, --canonicalize canonicalize printed paths
-D, --df imitate the output of df(1)
-d, --direction <word> direction of search, 'forward' or 'backward'
-e, --evaluate convert tags (LABEL,UUID,PARTUUID,PARTLABEL)
to device names
-F, --tab-file <path> alternative file for -s, -m or -k options
-f, --first-only print the first found filesystem only
-i, --invert invert the sense of matching
-J, --json use JSON output format
-l, --list use list format output
-N, --task <tid> use alternative namespace (/proc/<tid>/mountinfo file)
-n, --noheadings don't print column headings
-O, --options <list> limit the set of filesystems by mount options
-o, --output <list> the output columns to be shown
--output-all output all available columns
-P, --pairs use key="value" output format
--pseudo print only pseudo-filesystems
--shadowed print only filesystems over-mounted by another filesystem
-R, --submounts print all submounts for the matching filesystems
-r, --raw use raw output format
--real print only real filesystems
-S, --source <string> the device to mount (by name, maj:min,
LABEL=, UUID=, PARTUUID=, PARTLABEL=)
-T, --target <path> the path to the filesystem to use
--tree enable tree format output if possible
-M, --mountpoint <dir> the mountpoint directory
-t, --types <list> limit the set of filesystems by FS types
-U, --uniq ignore filesystems with duplicate target
-u, --notruncate don't truncate text in columns
-v, --nofsroot don't print [/dir] for bind or btrfs mounts
-y, --shell use column names to be usable as shell variable identifiers
-x, --verify verify mount table content (default is fstab)
--verbose print more details
--vfs-all print all VFS options
-h, --help display this help
-V, --version display version
Available output columns:
ACTION action detected by --poll
AVAIL filesystem size available
FREQ dump(8) period in days [fstab only]
FSROOT filesystem root
FSTYPE filesystem type
FS-OPTIONS FS specific mount options
ID mount ID
LABEL filesystem label
MAJ:MIN major:minor device number
OLD-OPTIONS old mount options saved by --poll
OLD-TARGET old mountpoint saved by --poll
OPTIONS all mount options
OPT-FIELDS optional mount fields
PARENT mount parent ID
PARTLABEL partition label
PARTUUID partition UUID
PASSNO pass number on parallel fsck(8) [fstab only]
PROPAGATION VFS propagation flags
SIZE filesystem size
SOURCE source device
SOURCES all possible source devices
TARGET mountpoint
TID task ID
USED filesystem size used
USE% filesystem use percentage
UUID filesystem UUID
VFS-OPTIONS VFS specific mount options
For more details see findmnt(8).flock
Manage locks from shell scripts
:~# flock -h
Usage:
flock [options] <file>|<directory> <command> [<argument>...]
flock [options] <file>|<directory> -c <command>
flock [options] <file descriptor number>
Manage file locks from shell scripts.
Options:
-s, --shared get a shared lock
-x, --exclusive get an exclusive lock (default)
-u, --unlock remove a lock
-n, --nonblock fail rather than wait
-w, --timeout <secs> wait for a limited amount of time
-E, --conflict-exit-code <number> exit code after conflict or timeout
-o, --close close file descriptor before running command
-c, --command <command> run a single command string through the shell
-F, --no-fork execute command without forking
--verbose increase verbosity
-h, --help display this help
-V, --version display version
For more details see flock(1).fsck
Check and repair a Linux filesystem
:~# fsck --help
Usage:
fsck [options] -- [fs-options] [<filesystem> ...]
Check and repair a Linux filesystem.
Options:
-A check all filesystems
-C [<fd>] display progress bar; file descriptor is for GUIs
-l lock the device to guarantee exclusive access
-M do not check mounted filesystems
-N do not execute, just show what would be done
-P check filesystems in parallel, including root
-R skip root filesystem; useful only with '-A'
-r [<fd>] report statistics for each device checked;
file descriptor is for GUIs
-s serialize the checking operations
-T do not show the title on startup
-t <type> specify filesystem types to be checked;
<type> is allowed to be a comma-separated list
-V explain what is being done
-?, --help display this help
--version display version
See the specific fsck.* commands for available fs-options.
For more details see fsck(8).fsck.cramfs
Fsck compressed ROM file system
:~# fsck.cramfs -h
Usage:
fsck.cramfs [options] <file>
Check and repair a compressed ROM filesystem.
Options:
-a for compatibility only, ignored
-v, --verbose be more verbose
-y for compatibility only, ignored
-b, --blocksize <size> use this blocksize, defaults to page size
--extract[=<dir>] test uncompression, optionally extract into <dir>
-h, --help display this help
-V, --version display version
For more details see fsck.cramfs(8).fsck.minix
Check consistency of Minix filesystem
:~# fsck.minix -h
Usage:
fsck.minix [options] <device>
Check the consistency of a Minix filesystem.
Options:
-l, --list list all filenames
-a, --auto automatic repair
-r, --repair interactive repair
-v, --verbose be verbose
-s, --super output super-block information
-m, --uncleared activate mode not cleared warnings
-f, --force force check
-h, --help display this help
-V, --version display version
For more details see fsck.minix(8).fsfreeze
Suspend access to a filesystem (Ext3/4, ReiserFS, JFS, XFS)
:~# fsfreeze -h
Usage:
fsfreeze [options] <mountpoint>
Suspend access to a filesystem.
Options:
-f, --freeze freeze the filesystem
-u, --unfreeze unfreeze the filesystem
-h, --help display this help
-V, --version display version
For more details see fsfreeze(8).fstrim
Discard unused blocks on a mounted filesystem
:~# fstrim -h
Usage:
fstrim [options] <mount point>
Discard unused blocks on a mounted filesystem.
Options:
-a, --all trim mounted filesystems
-A, --fstab trim filesystems from /etc/fstab
-I, --listed-in <list> trim filesystems listed in specified files
-o, --offset <num> the offset in bytes to start discarding from
-l, --length <num> the number of bytes to discard
-m, --minimum <num> the minimum extent length to discard
-v, --verbose print number of discarded bytes
--quiet-unsupported suppress error messages if trim unsupported
-n, --dry-run does everything, but trim
-h, --help display this help
-V, --version display version
Arguments:
<num> arguments may be followed by the suffixes for
GiB, TiB, PiB, EiB, ZiB, and YiB (the "iB" is optional)
For more details see fstrim(8).getopt
Parse command options (enhanced)
:~# getopt -h
Usage:
getopt <optstring> <parameters>
getopt [options] [--] <optstring> <parameters>
getopt [options] -o|--options <optstring> [options] [--] <parameters>
Parse command options.
Options:
-a, --alternative allow long options starting with single -
-l, --longoptions <longopts> the long options to be recognized
-n, --name <progname> the name under which errors are reported
-o, --options <optstring> the short options to be recognized
-q, --quiet disable error reporting by getopt(3)
-Q, --quiet-output no normal output
-s, --shell <shell> set quoting conventions to those of <shell>
-T, --test test for getopt(1) version
-u, --unquoted do not quote the output
-h, --help display this help
-V, --version display version
For more details see getopt(1).getty
Alternative Linux getty
:~# getty --help
Usage:
getty [options] <line> [<baud_rate>,...] [<termtype>]
getty [options] <baud_rate>,... <line> [<termtype>]
Open a terminal and set its mode.
Options:
-8, --8bits assume 8-bit tty
-a, --autologin <user> login the specified user automatically
-c, --noreset do not reset control mode
-E, --remote use -r <hostname> for login(1)
-f, --issue-file <list> display issue files or directories
--show-issue display issue file and exit
-h, --flow-control enable hardware flow control
-H, --host <hostname> specify login host
-i, --noissue do not display issue file
-I, --init-string <string> set init string
-J --noclear do not clear the screen before prompt
-l, --login-program <file> specify login program
-L, --local-line[=<mode>] control the local line flag
-m, --extract-baud extract baud rate during connect
-n, --skip-login do not prompt for login
-N --nonewline do not print a newline before issue
-o, --login-options <opts> options that are passed to login
-p, --login-pause wait for any key before the login
-r, --chroot <dir> change root to the directory
-R, --hangup do virtually hangup on the tty
-s, --keep-baud try to keep baud rate after break
-t, --timeout <number> login process timeout
-U, --detect-case detect uppercase terminal
-w, --wait-cr wait carriage-return
--nohints do not print hints
--nohostname no hostname at all will be shown
--long-hostname show full qualified hostname
--erase-chars <string> additional backspace chars
--kill-chars <string> additional kill chars
--chdir <directory> chdir before the login
--delay <number> sleep seconds before prompt
--nice <number> run login with this priority
--reload reload prompts on running agetty instances
--list-speeds display supported baud rates
--help display this help
--version display version
For more details see agetty(8).hardlink
Link multiple copies of a file
:~# hardlink -h
Usage:
hardlink [options] <directory>|<file> ...
Consolidate duplicate files using hardlinks.
Options:
-v, --verbose verbose output (repeat for more verbosity)
-q, --quiet quiet mode - don't print anything
-n, --dry-run don't actually link anything
-y, --method <name> file content comparison method
-f, --respect-name filenames have to be identical
-p, --ignore-mode ignore changes of file mode
-o, --ignore-owner ignore owner changes
-t, --ignore-time ignore timestamps (when testing for equality)
-c, --content compare only file contents, same as -pot
-X, --respect-xattrs respect extended attributes
--reflink[=<when>] create clone/CoW copies (auto, always, never)
--skip-reflinks skip already cloned files (enabled on --reflink)
-m, --maximize maximize the hardlink count, remove the file with
lowest hardlink count
-M, --minimize reverse the meaning of -m
-O, --keep-oldest keep the oldest file of multiple equal files
(lower precedence than minimize/maximize)
-x, --exclude <regex> regular expression to exclude files
-i, --include <regex> regular expression to include files/dirs
-s, --minimum-size <size> minimum size for files.
-S, --maximum-size <size> maximum size for files.
-b, --io-size <size> I/O buffer size for file reading (speedup, using more RAM)
-r, --cache-size <size> memory limit for cached file content data
-h, --help display this help
-V, --version display version
For more details see hardlink(1).i386
Change reported architecture in new program environment and/or set personality flags
:~# i386 -h
Usage:
i386 [options] [<program> [<argument>...]]
Change the reported architecture and set personality flags.
Options:
-B, --32bit turns on ADDR_LIMIT_32BIT
-F, --fdpic-funcptrs makes function pointers point to descriptors
-I, --short-inode turns on SHORT_INODE
-L, --addr-compat-layout changes the way virtual memory is allocated
-R, --addr-no-randomize disables randomization of the virtual address space
-S, --whole-seconds turns on WHOLE_SECONDS
-T, --sticky-timeouts turns on STICKY_TIMEOUTS
-X, --read-implies-exec turns on READ_IMPLIES_EXEC
-Z, --mmap-page-zero turns on MMAP_PAGE_ZERO
-3, --3gb limits the used address space to a maximum of 3 GB
--4gb ignored (for backward compatibility only)
--uname-2.6 turns on UNAME26
-v, --verbose say what options are being switched on
-h, --help display this help
-V, --version display version
For more details see setarch(8).ionice
Set or get process I/O scheduling class and priority
:~# ionice -h
Usage:
ionice [options] -p <pid>...
ionice [options] -P <pgid>...
ionice [options] -u <uid>...
ionice [options] <command>
Show or change the I/O-scheduling class and priority of a process.
Options:
-c, --class <class> name or number of scheduling class,
0: none, 1: realtime, 2: best-effort, 3: idle
-n, --classdata <num> priority (0..7) in the specified scheduling class,
only for the realtime and best-effort classes
-p, --pid <pid>... act on these already running processes
-P, --pgid <pgrp>... act on already running processes in these groups
-t, --ignore ignore failures
-u, --uid <uid>... act on already running processes owned by these users
-h, --help display this help
-V, --version display version
For more details see ionice(1).ipcmk
Make various IPC resources
:~# ipcmk -h
Usage:
ipcmk [options]
Create various IPC resources.
Options:
-M, --shmem <size> create shared memory segment of size <size>
-S, --semaphore <number> create semaphore array with <number> elements
-Q, --queue create message queue
-p, --mode <mode> permission for the resource (default is 0644)
-h, --help display this help
-V, --version display version
Arguments:
<size> arguments may be followed by the suffixes for
GiB, TiB, PiB, EiB, ZiB, and YiB (the "iB" is optional)
For more details see ipcmk(1).ipcrm
Remove certain IPC resources
:~# ipcrm -h
Usage:
ipcrm [options]
ipcrm shm|msg|sem <id>...
Remove certain IPC resources.
Options:
-m, --shmem-id <id> remove shared memory segment by id
-M, --shmem-key <key> remove shared memory segment by key
-q, --queue-id <id> remove message queue by id
-Q, --queue-key <key> remove message queue by key
-s, --semaphore-id <id> remove semaphore by id
-S, --semaphore-key <key> remove semaphore by key
-a, --all[=shm|msg|sem] remove all (in the specified category)
-v, --verbose explain what is being done
-h, --help display this help
-V, --version display version
For more details see ipcrm(1).ipcs
Show information on IPC facilities
:~# ipcs -h
Usage:
ipcs [resource-option...] [output-option]
ipcs -m|-q|-s -i <id>
Show information on IPC facilities.
Options:
-i, --id <id> print details on resource identified by <id>
-h, --help display this help
-V, --version display version
Resource options:
-m, --shmems shared memory segments
-q, --queues message queues
-s, --semaphores semaphores
-a, --all all (default)
Output options:
-t, --time show attach, detach and change times
-p, --pid show PIDs of creator and last operator
-c, --creator show creator and owner
-l, --limits show resource limits
-u, --summary show status summary
--human show sizes in human-readable format
-b, --bytes show sizes in bytes
For more details see ipcs(1).isosize
Output the length of an iso9660 filesystem
:~# isosize -h
Usage:
isosize [options] <iso9660_image_file> ...
Show the length of an ISO-9660 filesystem.
Options:
-d, --divisor=<number> divide the amount of bytes by <number>
-x, --sectors show sector count and size
-h, --help display this help
-V, --version display version
For more details see isosize(8).last
Show a listing of last logged in users
:~# last -h
Usage:
last [options] [<username>...] [<tty>...]
Show a listing of last logged in users.
Options:
-<number> how many lines to show
-a, --hostlast display hostnames in the last column
-d, --dns translate the IP number back into a hostname
-f, --file <file> use a specific file instead of /var/log/wtmp
-F, --fulltimes print full login and logout times and dates
-i, --ip display IP numbers in numbers-and-dots notation
-n, --limit <number> how many lines to show
-R, --nohostname don't display the hostname field
-s, --since <time> display the lines since the specified time
-t, --until <time> display the lines until the specified time
-p, --present <time> display who were present at the specified time
-w, --fullnames display full user and domain names
-x, --system display system shutdown entries and run level changes
--time-format <format> show timestamps in the specified <format>:
notime|short|full|iso
-h, --help display this help
-V, --version display version
For more details see last(1).lastb
Show a listing of last logged in users
:~# lastb -h
Usage:
lastb [options] [<username>...] [<tty>...]
Show a listing of last logged in users.
Options:
-<number> how many lines to show
-a, --hostlast display hostnames in the last column
-d, --dns translate the IP number back into a hostname
-f, --file <file> use a specific file instead of /var/log/btmp
-F, --fulltimes print full login and logout times and dates
-i, --ip display IP numbers in numbers-and-dots notation
-n, --limit <number> how many lines to show
-R, --nohostname don't display the hostname field
-s, --since <time> display the lines since the specified time
-t, --until <time> display the lines until the specified time
-p, --present <time> display who were present at the specified time
-w, --fullnames display full user and domain names
-x, --system display system shutdown entries and run level changes
--time-format <format> show timestamps in the specified <format>:
notime|short|full|iso
-h, --help display this help
-V, --version display version
For more details see last(1).ldattach
Attach a line discipline to a serial line
:~# ldattach -h
Usage:
ldattach [options] <ldisc> <device>
Attach a line discipline to a serial line.
Options:
-d, --debug print verbose messages to stderr
-s, --speed <value> set serial line speed
-c, --intro-command <string> intro sent before ldattach
-p, --pause <seconds> pause between intro and ldattach
-7, --sevenbits set character size to 7 bits
-8, --eightbits set character size to 8 bits
-n, --noparity set parity to none
-e, --evenparity set parity to even
-o, --oddparity set parity to odd
-1, --onestopbit set stop bits to one
-2, --twostopbits set stop bits to two
-i, --iflag [-]<iflag> set input mode flag
-h, --help display this help
-V, --version display version
Known <ldisc> names:
TTY SLIP MOUSE PPP STRIP
AX25 X25 6PACK R3964 IRDA
HDLC SYNC_PPP SYNCPPP HCI GIGASET_M101
M101 GIGASET PPS GSM0710
Known <iflag> names:
IGNBRK BRKINT IGNPAR PARMRK INPCK
ISTRIP INLCR IGNCR ICRNL IUCLC
IXON IXANY IXOFF IMAXBEL IUTF8
For more details see ldattach(8).linux32
Change reported architecture in new program environment and/or set personality flags
:~# linux32 -h
Usage:
linux32 [options] [<program> [<argument>...]]
Change the reported architecture and set personality flags.
Options:
-B, --32bit turns on ADDR_LIMIT_32BIT
-F, --fdpic-funcptrs makes function pointers point to descriptors
-I, --short-inode turns on SHORT_INODE
-L, --addr-compat-layout changes the way virtual memory is allocated
-R, --addr-no-randomize disables randomization of the virtual address space
-S, --whole-seconds turns on WHOLE_SECONDS
-T, --sticky-timeouts turns on STICKY_TIMEOUTS
-X, --read-implies-exec turns on READ_IMPLIES_EXEC
-Z, --mmap-page-zero turns on MMAP_PAGE_ZERO
-3, --3gb limits the used address space to a maximum of 3 GB
--4gb ignored (for backward compatibility only)
--uname-2.6 turns on UNAME26
-v, --verbose say what options are being switched on
-h, --help display this help
-V, --version display version
For more details see setarch(8).linux64
Change reported architecture in new program environment and/or set personality flags
:~# linux64 -h
Usage:
linux64 [options] [<program> [<argument>...]]
Change the reported architecture and set personality flags.
Options:
-B, --32bit turns on ADDR_LIMIT_32BIT
-F, --fdpic-funcptrs makes function pointers point to descriptors
-I, --short-inode turns on SHORT_INODE
-L, --addr-compat-layout changes the way virtual memory is allocated
-R, --addr-no-randomize disables randomization of the virtual address space
-S, --whole-seconds turns on WHOLE_SECONDS
-T, --sticky-timeouts turns on STICKY_TIMEOUTS
-X, --read-implies-exec turns on READ_IMPLIES_EXEC
-Z, --mmap-page-zero turns on MMAP_PAGE_ZERO
-3, --3gb limits the used address space to a maximum of 3 GB
--4gb ignored (for backward compatibility only)
--uname-2.6 turns on UNAME26
-v, --verbose say what options are being switched on
-h, --help display this help
-V, --version display version
For more details see setarch(8).lsblk
List block devices
:~# lsblk -h
Usage:
lsblk [options] [<device> ...]
List information about block devices.
Options:
-A, --noempty don't print empty devices
-D, --discard print discard capabilities
-E, --dedup <column> de-duplicate output by <column>
-I, --include <list> show only devices with specified major numbers
-J, --json use JSON output format
-M, --merge group parents of sub-trees (usable for RAIDs, Multi-path)
-O, --output-all output all columns
-P, --pairs use key="value" output format
-S, --scsi output info about SCSI devices
-T, --tree[=<column>] use tree format output
-a, --all print all devices
-b, --bytes print SIZE in bytes rather than in human readable format
-d, --nodeps don't print slaves or holders
-e, --exclude <list> exclude devices by major number (default: RAM disks)
-f, --fs output info about filesystems
-i, --ascii use ascii characters only
-l, --list use list format output
-m, --perms output info about permissions
-n, --noheadings don't print headings
-o, --output <list> output columns
-p, --paths print complete device path
-r, --raw use raw output format
-s, --inverse inverse dependencies
-t, --topology output info about topology
-w, --width <num> specifies output width as number of characters
-x, --sort <column> sort output by <column>
-y, --shell use column names to be usable as shell variable identifiers
-z, --zoned print zone related information
--sysroot <dir> use specified directory as system root
-h, --help display this help
-V, --version display version
Available output columns:
ALIGNMENT alignment offset
DISC-ALN discard alignment offset
DAX dax-capable device
DISC-GRAN discard granularity
DISC-MAX discard max bytes
DISC-ZERO discard zeroes data
FSAVAIL filesystem size available
FSROOTS mounted filesystem roots
FSSIZE filesystem size
FSTYPE filesystem type
FSUSED filesystem size used
FSUSE% filesystem use percentage
FSVER filesystem version
GROUP group name
HCTL Host:Channel:Target:Lun for SCSI
HOTPLUG removable or hotplug device (usb, pcmcia, ...)
KNAME internal kernel device name
LABEL filesystem LABEL
LOG-SEC logical sector size
MAJ:MIN major:minor device number
MIN-IO minimum I/O size
MODE device node permissions
MODEL device identifier
NAME device name
OPT-IO optimal I/O size
OWNER user name
PARTFLAGS partition flags
PARTLABEL partition LABEL
PARTTYPE partition type code or UUID
PARTTYPENAME partition type name
PARTUUID partition UUID
PATH path to the device node
PHY-SEC physical sector size
PKNAME internal parent kernel device name
PTTYPE partition table type
PTUUID partition table identifier (usually UUID)
RA read-ahead of the device
RAND adds randomness
REV device revision
RM removable device
RO read-only device
ROTA rotational device
RQ-SIZE request queue size
SCHED I/O scheduler name
SERIAL disk serial number
SIZE size of the device
START partition start offset
STATE state of the device
SUBSYSTEMS de-duplicated chain of subsystems
MOUNTPOINT where the device is mounted
MOUNTPOINTS all locations where device is mounted
TRAN device transport type
TYPE device type
UUID filesystem UUID
VENDOR device vendor
WSAME write same max bytes
WWN unique storage identifier
ZONED zone model
ZONE-SZ zone size
ZONE-WGRAN zone write granularity
ZONE-APP zone append max bytes
ZONE-NR number of zones
ZONE-OMAX maximum number of open zones
ZONE-AMAX maximum number of active zones
For more details see lsblk(8).lscpu
Display information about the CPU architecture
:~# lscpu -h
Usage:
lscpu [options]
Display information about the CPU architecture.
Options:
-a, --all print both online and offline CPUs (default for -e)
-b, --online print online CPUs only (default for -p)
-B, --bytes print sizes in bytes rather than in human readable format
-C, --caches[=<list>] info about caches in extended readable format
-c, --offline print offline CPUs only
-J, --json use JSON for default or extended format
-e, --extended[=<list>] print out an extended readable format
-p, --parse[=<list>] print out a parsable format
-s, --sysroot <dir> use specified directory as system root
-x, --hex print hexadecimal masks rather than lists of CPUs
-y, --physical print physical instead of logical IDs
--output-all print all available columns for -e, -p or -C
-h, --help display this help
-V, --version display version
Available output columns for -e or -p:
BOGOMIPS crude measurement of CPU speed
CPU logical CPU number
CORE logical core number
SOCKET logical socket number
CLUSTER logical cluster number
NODE logical NUMA node number
BOOK logical book number
DRAWER logical drawer number
CACHE shows how caches are shared between CPUs
POLARIZATION CPU dispatching mode on virtual hardware
ADDRESS physical address of a CPU
CONFIGURED shows if the hypervisor has allocated the CPU
ONLINE shows if Linux currently makes use of the CPU
MHZ shows the currently MHz of the CPU
SCALMHZ% shows scaling percentage of the CPU frequency
MAXMHZ shows the maximum MHz of the CPU
MINMHZ shows the minimum MHz of the CPU
Available output columns for -C:
ALL-SIZE size of all system caches
LEVEL cache level
NAME cache name
ONE-SIZE size of one cache
TYPE cache type
WAYS ways of associativity
ALLOC-POLICY allocation policy
WRITE-POLICY write policy
PHY-LINE number of physical cache line per cache t
SETS number of sets in the cache; set lines has the same cache index
COHERENCY-SIZE minimum amount of data in bytes transferred from memory to cache
For more details see lscpu(1).lsipc
Show information on IPC facilities currently employed in the system
:~# lsipc -h
Usage:
lsipc [options]
Show information on IPC facilities.
Resource options:
-m, --shmems shared memory segments
-q, --queues message queues
-s, --semaphores semaphores
-g, --global info about system-wide usage (may be used with -m, -q and -s)
-i, --id <id> print details on resource identified by <id>
Options:
--noheadings don't print headings
--notruncate don't truncate output
--time-format=<type> display dates in short, full or iso format
-b, --bytes print SIZE in bytes rather than in human readable format
-c, --creator show creator and owner
-e, --export display in an export-able output format
-J, --json use the JSON output format
-n, --newline display each piece of information on a new line
-l, --list force list output format (for example with --id)
-o, --output[=<list>] define the columns to output
-P, --numeric-perms print numeric permissions (PERMS column)
-r, --raw display in raw mode
-t, --time show attach, detach and change times
-y, --shell use column names to be usable as shell variable identifiers
-h, --help display this help
-V, --version display version
Generic columns:
KEY Resource key
ID Resource ID
OWNER Owner's username or UID
PERMS Permissions
CUID Creator UID
CUSER Creator user
CGID Creator GID
CGROUP Creator group
UID User ID
USER User name
GID Group ID
GROUP Group name
CTIME Time of the last change
Shared-memory columns (--shmems):
SIZE Segment size
NATTCH Number of attached processes
STATUS Status
ATTACH Attach time
DETACH Detach time
COMMAND Creator command line
CPID PID of the creator
LPID PID of last user
Message-queue columns (--queues):
USEDBYTES Bytes used
MSGS Number of messages
SEND Time of last msg sent
RECV Time of last msg received
LSPID PID of the last msg sender
LRPID PID of the last msg receiver
Semaphore columns (--semaphores):
NSEMS Number of semaphores
OTIME Time of the last operation
Summary columns (--global):
RESOURCE Resource name
DESCRIPTION Resource description
LIMIT System-wide limit
USED Currently used
USE% Currently use percentage
For more details see lsipc(1).lslocks
List local system locks
:~# lslocks -h
Usage:
lslocks [options]
List local system locks.
Options:
-b, --bytes print SIZE in bytes rather than in human readable format
-J, --json use JSON output format
-i, --noinaccessible ignore locks without read permissions
-n, --noheadings don't print headings
-o, --output <list> define which output columns to use
--output-all output all columns
-p, --pid <pid> display only locks held by this process
-r, --raw use the raw output format
-u, --notruncate don't truncate text in columns
-h, --help display this help
-V, --version display version
Available output columns:
COMMAND command of the process holding the lock
PID PID of the process holding the lock
TYPE kind of lock
SIZE size of the lock
INODE inode number
MAJ:MIN major:minor device number
MODE lock access mode
M mandatory state of the lock: 0 (none), 1 (set)
START relative byte offset of the lock
END ending offset of the lock
PATH path of the locked file
BLOCKER PID of the process blocking the lock
For more details see lslocks(8).lslogins
Display information about known users in the system
:~# lslogins -h
Usage:
lslogins [options] [<username>]
Display information about known users in the system.
Options:
-a, --acc-expiration display info about passwords expiration
-c, --colon-separate display data in a format similar to /etc/passwd
-e, --export display in an export-able output format
-f, --failed display data about the users' last failed logins
-G, --supp-groups display information about groups
-g, --groups=<groups> display users belonging to a group in <groups>
-L, --last show info about the users' last login sessions
-l, --logins=<logins> display only users from <logins>
-n, --newline display each piece of information on a new line
--noheadings don't print headings
--notruncate don't truncate output
-o, --output[=<list>] define the columns to output
--output-all output all columns
-p, --pwd display information related to login by password.
-r, --raw display in raw mode
-s, --system-accs display system accounts
--time-format=<type> display dates in short, full or iso format
-u, --user-accs display user accounts
-y, --shell use column names to be usable as shell variable identifiers
-Z, --context display SELinux contexts
-z, --print0 delimit user entries with a nul character
--wtmp-file <path> set an alternate path for wtmp
--btmp-file <path> set an alternate path for btmp
--lastlog <path> set an alternate path for lastlog
-h, --help display this help
-V, --version display version
Available output columns:
USER user name
UID user ID
GECOS full user name
HOMEDIR home directory
SHELL login shell
NOLOGIN log in disabled by nologin(8) or pam_nologin(8)
PWD-LOCK password defined, but locked
PWD-EMPTY password not defined
PWD-DENY login by password disabled
PWD-METHOD password encryption method
GROUP primary group name
GID primary group ID
SUPP-GROUPS supplementary group names
SUPP-GIDS supplementary group IDs
LAST-LOGIN date of last login
LAST-TTY last tty used
LAST-HOSTNAME hostname during the last session
FAILED-LOGIN date of last failed login
FAILED-TTY where did the login fail?
HUSHED user's hush settings
PWD-WARN days user is warned of password expiration
PWD-CHANGE date of last password change
PWD-MIN number of days required between changes
PWD-MAX max number of days a password may remain unchanged
PWD-EXPIR password expiration date
CONTEXT the user's security context
PROC number of processes run by the user
For more details see lslogins(1).lsmem
List the ranges of available memory with their online status
:~# lsmem -h
Usage:
lsmem [options]
List the ranges of available memory with their online status.
Options:
-J, --json use JSON output format
-P, --pairs use key="value" output format
-a, --all list each individual memory block
-b, --bytes print SIZE in bytes rather than in human readable format
-n, --noheadings don't print headings
-o, --output <list> output columns
--output-all output all columns
-r, --raw use raw output format
-S, --split <list> split ranges by specified columns
-s, --sysroot <dir> use the specified directory as system root
--summary[=when] print summary information (never,always or only)
-h, --help display this help
-V, --version display version
Available output columns:
RANGE start and end address of the memory range
SIZE size of the memory range
STATE online status of the memory range
REMOVABLE memory is removable
BLOCK memory block number or blocks range
NODE numa node of memory
ZONES valid zones for the memory range
For more details see lsmem(1).lsns
List namespaces
:~# lsns -h
Usage:
lsns [options] [<namespace>]
List system namespaces.
Options:
-J, --json use JSON output format
-l, --list use list format output
-n, --noheadings don't print headings
-o, --output <list> define which output columns to use
--output-all output all columns
-p, --task <pid> print process namespaces
-r, --raw use the raw output format
-u, --notruncate don't truncate text in columns
-W, --nowrap don't use multi-line representation
-t, --type <name> namespace type (mnt, net, ipc, user, pid, uts, cgroup, time)
-T, --tree <rel> use tree format (parent, owner, or process)
-h, --help display this help
-V, --version display version
Available output columns:
NS namespace identifier (inode number)
TYPE kind of namespace
PATH path to the namespace
NPROCS number of processes in the namespace
PID lowest PID in the namespace
PPID PPID of the PID
COMMAND command line of the PID
UID UID of the PID
USER username of the PID
NETNSID namespace ID as used by network subsystem
NSFS nsfs mountpoint (usually used network subsystem)
PNS parent namespace identifier (inode number)
ONS owner namespace identifier (inode number)
For more details see lsns(8).mcookie
Generate magic cookies for xauth
:~# mcookie -h
Usage:
mcookie [options]
Generate magic cookies for xauth.
Options:
-f, --file <file> use file as a cookie seed
-m, --max-size <num> limit how much is read from seed files
-v, --verbose explain what is being done
-h, --help display this help
-V, --version display version
Arguments:
<num> arguments may be followed by the suffixes for
GiB, TiB, PiB, EiB, ZiB, and YiB (the "iB" is optional)
For more details see mcookie(1).mesg
Display (or do not display) messages from other users
:~# mesg -h
Usage:
mesg [options] [y | n]
Control write access of other users to your terminal.
Options:
-v, --verbose explain what is being done
-h, --help display this help
-V, --version display version
For more details see mesg(1).mkfs
Build a Linux filesystem
:~# mkfs -h
Usage:
mkfs [options] [-t <type>] [fs-options] <device> [<size>]
Make a Linux filesystem.
Options:
-t, --type=<type> filesystem type; when unspecified, ext2 is used
fs-options parameters for the real filesystem builder
<device> path to the device to be used
<size> number of blocks to be used on the device
-V, --verbose explain what is being done;
specifying -V more than once will cause a dry-run
-h, --help display this help
-V, --version display version
For more details see mkfs(8).mkfs.bfs
Make an SCO bfs filesystem
:~# mkfs.bfs -h
Usage: mkfs.bfs [options] device [block-count]
Make an SCO bfs filesystem.
Options:
-N, --inodes=NUM specify desired number of inodes
-V, --vname=NAME specify volume name
-F, --fname=NAME specify file system name
-v, --verbose explain what is being done
-c this option is silently ignored
-l this option is silently ignored
-h, --help display this help
-V, --version display version
For more details see mkfs.bfs(8).mkfs.cramfs
Make compressed ROM file system
:~# mkfs.cramfs -h
Usage:
mkfs.cramfs [-h] [-v] [-b blksize] [-e edition] [-N endian] [-i file] [-n name] dirname outfile
Make compressed ROM file system.
Options:
-v be verbose
-E make all warnings errors (non-zero exit status)
-b blksize use this blocksize, must equal page size
-e edition set edition number (part of fsid)
-N endian set cramfs endianness (big|little|host), default host
-i file insert a file image into the filesystem
-n name set name of cramfs filesystem
-p pad by 512 bytes for boot code
-s sort directory entries (old option, ignored)
-z make explicit holes
dirname root of the filesystem to be compressed
outfile output file
-h, --help display this help
-V, --version display version
For more details see mkfs.cramfs(8).mkfs.minix
Make a Minix filesystem
:~# mkfs.minix -h
Usage:
mkfs.minix [options] /dev/name [blocks]
Options:
-1 use Minix version 1
-2, -v use Minix version 2
-3 use Minix version 3
-n, --namelength <num> maximum length of filenames
-i, --inodes <num> number of inodes for the filesystem
-c, --check check the device for bad blocks
-l, --badblocks <file> list of bad blocks from file
--lock[=<mode>] use exclusive device lock (yes, no or nonblock)
-h, --help display this help
-V, --version display version
For more details see mkfs.minix(8).mkswap
Set up a Linux swap area
:~# mkswap -h
Usage:
mkswap [options] device [size]
Set up a Linux swap area.
Options:
-c, --check check bad blocks before creating the swap area
-f, --force allow swap size area be larger than device
-q, --quiet suppress output and warning messages
-p, --pagesize SIZE specify page size in bytes
-L, --label LABEL specify label
-v, --swapversion NUM specify swap-space version number
-U, --uuid UUID specify the uuid to use
--verbose verbose output
--lock[=<mode>] use exclusive device lock (yes, no or nonblock)
-h, --help display this help
-V, --version display version
For more details see mkswap(8).more
File perusal filter for crt viewing
:~# more -h
Usage:
more [options] <file>...
A file perusal filter for CRT viewing.
Options:
-d, --silent display help instead of ringing bell
-f, --logical count logical rather than screen lines
-l, --no-pause suppress pause after form feed
-c, --print-over do not scroll, display text and clean line ends
-p, --clean-print do not scroll, clean screen and display text
-e, --exit-on-eof exit on end-of-file
-s, --squeeze squeeze multiple blank lines into one
-u, --plain suppress underlining and bold
-n, --lines <number> the number of lines per screenful
-<number> same as --lines
+<number> display file beginning from line number
+/<pattern> display file beginning from pattern match
-h, --help display this help
-V, --version display version
For more details see more(1).mountpoint
See if a directory or file is a mountpoint
:~# mountpoint -h
Usage:
mountpoint [-qd] /path/to/directory
mountpoint -x /dev/device
Check whether a directory or file is a mountpoint.
Options:
-q, --quiet quiet mode - don't print anything
--nofollow do not follow symlink
-d, --fs-devno print maj:min device number of the filesystem
-x, --devno print maj:min device number of the block device
-h, --help display this help
-V, --version display version
For more details see mountpoint(1).namei
Follow a pathname until a terminal point is found
:~# namei -h
Usage:
namei [options] <pathname>...
Follow a pathname until a terminal point is found.
Options:
-x, --mountpoints show mount point directories with a 'D'
-m, --modes show the mode bits of each file
-o, --owners show owner and group name of each file
-l, --long use a long listing format (-m -o -v)
-n, --nosymlinks don't follow symlinks
-v, --vertical vertical align of modes and owners
-h, --help display this help
-V, --version display version
For more details see namei(1).nsenter
Run program in different namespaces
:~# nsenter -h
Usage:
nsenter [options] [<program> [<argument>...]]
Run a program with namespaces of other processes.
Options:
-a, --all enter all namespaces
-t, --target <pid> target process to get namespaces from
-m, --mount[=<file>] enter mount namespace
-u, --uts[=<file>] enter UTS namespace (hostname etc)
-i, --ipc[=<file>] enter System V IPC namespace
-n, --net[=<file>] enter network namespace
-p, --pid[=<file>] enter pid namespace
-C, --cgroup[=<file>] enter cgroup namespace
-U, --user[=<file>] enter user namespace
-T, --time[=<file>] enter time namespace
-S, --setuid <uid> set uid in entered namespace
-G, --setgid <gid> set gid in entered namespace
--preserve-credentials do not touch uids or gids
-r, --root[=<dir>] set the root directory
-w, --wd[=<dir>] set the working directory
-W. --wdns <dir> set the working directory in namespace
-F, --no-fork do not fork before exec'ing <program>
-Z, --follow-context set SELinux context according to --target PID
-h, --help display this help
-V, --version display version
For more details see nsenter(1).partx
Tell the kernel about the presence and numbering of on-disk partitions
:~# partx -h
Usage:
partx [-a|-d|-s|-u] [--nr <n:m> | <partition>] <disk>
Tell the kernel about the presence and numbering of partitions.
Options:
-a, --add add specified partitions or all of them
-d, --delete delete specified partitions or all of them
-u, --update update specified partitions or all of them
-s, --show list partitions
-b, --bytes print SIZE in bytes rather than in human readable format
-g, --noheadings don't print headings for --show
-n, --nr <n:m> specify the range of partitions (e.g. --nr 2:4)
-o, --output <list> define which output columns to use
--output-all output all columns
-P, --pairs use key="value" output format
-r, --raw use raw output format
-S, --sector-size <num> overwrite sector size
-t, --type <type> specify the partition type
--list-types list supported partition types and exit
-v, --verbose verbose mode
-h, --help display this help
-V, --version display version
Available output columns:
NR partition number
START start of the partition in sectors
END end of the partition in sectors
SECTORS number of sectors
SIZE human readable size
NAME partition name
UUID partition UUID
TYPE partition type (a string, a UUID, or hex)
FLAGS partition flags
SCHEME partition table type (dos, gpt, ...)
For more details see partx(8).pivot_root
Change the root filesystem
:~# pivot_root -h
Usage:
pivot_root [options] new_root put_old
Change the root filesystem.
Options:
-h, --help display this help
-V, --version display version
For more details see pivot_root(8).prlimit
Get and set process resource limits
:~# prlimit -h
Usage:
prlimit [options] [--<resource>=<limit>] [-p PID]
prlimit [options] [--<resource>=<limit>] COMMAND
Show or change the resource limits of a process.
Options:
-p, --pid <pid> process id
-o, --output <list> define which output columns to use
--noheadings don't print headings
--raw use the raw output format
--verbose verbose output
-h, --help display this help
-V, --version display version
Resources:
-c, --core maximum size of core files created
-d, --data maximum size of a process's data segment
-e, --nice maximum nice priority allowed to raise
-f, --fsize maximum size of files written by the process
-i, --sigpending maximum number of pending signals
-l, --memlock maximum size a process may lock into memory
-m, --rss maximum resident set size
-n, --nofile maximum number of open files
-q, --msgqueue maximum bytes in POSIX message queues
-r, --rtprio maximum real-time scheduling priority
-s, --stack maximum stack size
-t, --cpu maximum amount of CPU time in seconds
-u, --nproc maximum number of user processes
-v, --as size of virtual memory
-x, --locks maximum number of file locks
-y, --rttime CPU time in microseconds a process scheduled
under real-time scheduling
Arguments:
<limit> is defined as a range soft:hard, soft:, :hard or a value to
define both limits (e.g. -e=0:10 -r=:10).
Available output columns:
DESCRIPTION resource description
RESOURCE resource name
SOFT soft limit
HARD hard limit (ceiling)
UNITS units
For more details see prlimit(1).readprofile
Read kernel profiling information
:~# readprofile -h
Usage:
readprofile [options]
Display kernel profiling information.
Options:
-m, --mapfile <mapfile> (defaults: "/boot/System.map" and
"/boot/System.map-6.1.0-kali5-amd64")
-p, --profile <pro-file> (default: "/proc/profile")
-M, --multiplier <mult> set the profiling multiplier to <mult>
-i, --info print only info about the sampling step
-v, --verbose print verbose data
-a, --all print all symbols, even if count is 0
-b, --histbin print individual histogram-bin counts
-s, --counters print individual counters within functions
-r, --reset reset all the counters (root only)
-n, --no-auto disable byte order auto-detection
-h, --help display this help
-V, --version display version
For more details see readprofile(8).rename.ul
Rename files
:~# rename.ul -h
Usage:
rename.ul [options] <expression> <replacement> <file>...
Rename files.
Options:
-v, --verbose explain what is being done
-s, --symlink act on the target of symlinks
-n, --no-act do not make any changes
-a, --all replace all occurrences
-l, --last replace only the last occurrence
-o, --no-overwrite don't overwrite existing files
-i, --interactive prompt before overwrite
-h, --help display this help
-V, --version display version
For more details see rename(1).resizepart
Tell the kernel about the new size of a partition
:~# resizepart -h
Usage:
resizepart <disk device> <partition number> <length>
Tell the kernel about the new size of a partition.
Options:
-h, --help display this help
-V, --version display version
For more details see resizepart(8).rev
Reverse lines characterwise
:~# rev -h
Usage: rev [options] [file ...]
Reverse lines characterwise.
Options:
-h, --help display this help
-V, --version display version
For more details see rev(1).rtcwake
Enter a system sleep state until specified wakeup time
:~# rtcwake -h
Usage:
rtcwake [options]
Enter a system sleep state until a specified wakeup time.
Options:
-a, --auto reads the clock mode from adjust file (default)
-A, --adjfile <file> specifies the path to the adjust file
the default is /etc/adjtime
--date <timestamp> date time of timestamp to wake
-d, --device <device> select rtc device (rtc0|rtc1|...)
-n, --dry-run does everything, but suspend
-l, --local RTC uses local timezone
--list-modes list available modes
-m, --mode <mode> standby|mem|... sleep mode
-s, --seconds <seconds> seconds to sleep
-t, --time <time_t> time to wake
-u, --utc RTC uses UTC
-v, --verbose verbose messages
-h, --help display this help
-V, --version display version
For more details see rtcwake(8).runuser
Run a command with substitute user and group ID
:~# runuser -h
Usage:
runuser [options] -u <user> [[--] <command>]
runuser [options] [-] [<user> [<argument>...]]
Run <command> with the effective user ID and group ID of <user>. If -u is
not given, fall back to su(1)-compatible semantics and execute standard shell.
The options -c, -f, -l, and -s are mutually exclusive with -u.
Options:
-u, --user <user> username
-m, -p, --preserve-environment do not reset environment variables
-w, --whitelist-environment <list> don't reset specified variables
-g, --group <group> specify the primary group
-G, --supp-group <group> specify a supplemental group
-, -l, --login make the shell a login shell
-c, --command <command> pass a single command to the shell with -c
--session-command <command> pass a single command to the shell with -c
and do not create a new session
-f, --fast pass -f to the shell (for csh or tcsh)
-s, --shell <shell> run <shell> if /etc/shells allows it
-P, --pty create a new pseudo-terminal
-h, --help display this help
-V, --version display version
For more details see runuser(1).setarch
Change reported architecture in new program environment and/or set personality flags
:~# setarch -h
Usage:
setarch [<arch>] [options] [<program> [<argument>...]]
Change the reported architecture and set personality flags.
Options:
-B, --32bit turns on ADDR_LIMIT_32BIT
-F, --fdpic-funcptrs makes function pointers point to descriptors
-I, --short-inode turns on SHORT_INODE
-L, --addr-compat-layout changes the way virtual memory is allocated
-R, --addr-no-randomize disables randomization of the virtual address space
-S, --whole-seconds turns on WHOLE_SECONDS
-T, --sticky-timeouts turns on STICKY_TIMEOUTS
-X, --read-implies-exec turns on READ_IMPLIES_EXEC
-Z, --mmap-page-zero turns on MMAP_PAGE_ZERO
-3, --3gb limits the used address space to a maximum of 3 GB
--4gb ignored (for backward compatibility only)
--uname-2.6 turns on UNAME26
-v, --verbose say what options are being switched on
--list list settable architectures, and exit
-h, --help display this help
-V, --version display version
For more details see setarch(8).setpriv
Run a program with different Linux privilege settings
:~# setpriv -h
Usage:
setpriv [options] <program> [<argument>...]
Run a program with different privilege settings.
Options:
-d, --dump show current state (and do not exec)
--nnp, --no-new-privs disallow granting new privileges
--ambient-caps <caps,...> set ambient capabilities
--inh-caps <caps,...> set inheritable capabilities
--bounding-set <caps> set capability bounding set
--ruid <uid|user> set real uid
--euid <uid|user> set effective uid
--rgid <gid|user> set real gid
--egid <gid|group> set effective gid
--reuid <uid|user> set real and effective uid
--regid <gid|group> set real and effective gid
--clear-groups clear supplementary groups
--keep-groups keep supplementary groups
--init-groups initialize supplementary groups
--groups <group,...> set supplementary groups by UID or name
--securebits <bits> set securebits
--pdeathsig keep|clear|<signame>
set or clear parent death signal
--selinux-label <label> set SELinux label
--apparmor-profile <pr> set AppArmor profile
--reset-env clear all environment and initialize
HOME, SHELL, USER, LOGNAME and PATH
-h, --help display this help
-V, --version display version
This tool can be dangerous. Read the manpage, and be careful.
For more details see setpriv(1).setsid
Run a program in a new session
:~# setsid -h
Usage:
setsid [options] <program> [arguments ...]
Run a program in a new session.
Options:
-c, --ctty set the controlling terminal to the current one
-f, --fork always fork
-w, --wait wait program to exit, and use the same return
-h, --help display this help
-V, --version display version
For more details see setsid(1).setterm
Set terminal attributes
:~# setterm --help
Usage:
setterm [options]
Set the attributes of a terminal.
Options:
--term <terminal_name> override TERM environment variable
--reset reset terminal to power-on state
--resize reset terminal rows and columns
--initialize display init string, and use default settings
--default use default terminal settings
--store save current terminal settings as default
--cursor on|off display cursor
--repeat on|off keyboard repeat
--appcursorkeys on|off cursor key application mode
--linewrap on|off continue on a new line when a line is full
--inversescreen on|off swap colors for the whole screen
--msg on|off send kernel messages to console
--msglevel <0-8> kernel console log level
--foreground default|<color> set foreground color
--background default|<color> set background color
--ulcolor [bright] <color> set underlined text color
--hbcolor [bright] <color> set half-bright text color
<color>: black blue cyan green grey magenta red white yellow
--bold on|off bold
--half-bright on|off dim
--blink on|off blink
--underline on|off underline
--reverse on|off swap foreground and background colors
--clear[=<all|rest>] clear screen and set cursor position
--tabs[=<number>...] set these tab stop positions, or show them
--clrtabs[=<number>...] clear these tab stop positions, or all
--regtabs[=1-160] set a regular tab stop interval
--blank[=0-60|force|poke] set time of inactivity before screen blanks
--dump[=<number>] write vcsa<number> console dump to file
--append <number> append vcsa<number> console dump to file
--file <filename> name of the dump file
--powersave on|vsync|hsync|powerdown|off
set vesa powersaving features
--powerdown[=<0-60>] set vesa powerdown interval in minutes
--blength[=<0-2000>] duration of the bell in milliseconds
--bfreq[=<number>] bell frequency in Hertz
--help display this help
--version display version
For more details see setterm(1).su
Run a command with substitute user and group ID
:~# su -h
Usage:
su [options] [-] [<user> [<argument>...]]
Change the effective user ID and group ID to that of <user>.
A mere - implies -l. If <user> is not given, root is assumed.
Options:
-m, -p, --preserve-environment do not reset environment variables
-w, --whitelist-environment <list> don't reset specified variables
-g, --group <group> specify the primary group
-G, --supp-group <group> specify a supplemental group
-, -l, --login make the shell a login shell
-c, --command <command> pass a single command to the shell with -c
--session-command <command> pass a single command to the shell with -c
and do not create a new session
-f, --fast pass -f to the shell (for csh or tcsh)
-s, --shell <shell> run <shell> if /etc/shells allows it
-P, --pty create a new pseudo-terminal
-h, --help display this help
-V, --version display version
For more details see su(1).sulogin
Single-user login
:~# sulogin -h
Usage:
sulogin [options] [tty device]
Single-user login.
Options:
-p, --login-shell start a login shell
-t, --timeout <seconds> max time to wait for a password (default: no limit)
-e, --force examine password files directly if getpwnam(3) fails
-h, --help display this help
-V, --version display version
For more details see sulogin(8).swaplabel
Print or change the label or UUID of a swap area
:~# swaplabel -h
Usage:
swaplabel [options] <device>
Display or change the label or UUID of a swap area.
Options:
-L, --label <label> specify a new label
-U, --uuid <uuid> specify a new uuid
-h, --help display this help
-V, --version display version
For more details see swaplabel(8).switch_root
Switch to another filesystem as the root of the mount tree
:~# switch_root -h
Usage:
switch_root [options] <newrootdir> <init> <args to init>
Switch to another filesystem as the root of the mount tree.
Options:
-h, --help display this help
-V, --version display version
For more details see switch_root(8).taskset
Set or retrieve a process’s CPU affinity
:~# taskset -h
Usage: taskset [options] [mask | cpu-list] [pid|cmd [args...]]
Show or change the CPU affinity of a process.
Options:
-a, --all-tasks operate on all the tasks (threads) for a given pid
-p, --pid operate on existing given pid
-c, --cpu-list display and specify cpus in list format
-h, --help display this help
-V, --version display version
The default behavior is to run a new command:
taskset 03 sshd -b 1024
You can retrieve the mask of an existing task:
taskset -p 700
Or set it:
taskset -p 03 700
List format uses a comma-separated list instead of a mask:
taskset -pc 0,3,7-11 700
Ranges in list format can take a stride argument:
e.g. 0-31:2 is equivalent to mask 0x55555555
For more details see taskset(1).uclampset
Manipulate the utilization clamping attributes of the system or a process
:~# uclampset -h
Usage:
uclampset [options]
uclampset [options] --pid <pid> | --system | <command> <arg>...
Show or change the utilization clamping attributes.
Options:
-m <value> util_min value to set
-M <value> util_max value to set
-a, --all-tasks operate on all the tasks (threads) for a given pid
-p, --pid <pid> operate on existing given pid
-s, --system operate on system
-R, --reset-on-fork set reset-on-fork flag
-v, --verbose display status information
-h, --help display this help
-V, --version display version
Utilization value range is [0:1024]. Use special -1 value to reset to system's default.
For more details see uclampset(1).unshare
Run program in new namespaces
:~# unshare -h
Usage:
unshare [options] [<program> [<argument>...]]
Run a program with some namespaces unshared from the parent.
Options:
-m, --mount[=<file>] unshare mounts namespace
-u, --uts[=<file>] unshare UTS namespace (hostname etc)
-i, --ipc[=<file>] unshare System V IPC namespace
-n, --net[=<file>] unshare network namespace
-p, --pid[=<file>] unshare pid namespace
-U, --user[=<file>] unshare user namespace
-C, --cgroup[=<file>] unshare cgroup namespace
-T, --time[=<file>] unshare time namespace
-f, --fork fork before launching <program>
--map-user=<uid>|<name> map current user to uid (implies --user)
--map-group=<gid>|<name> map current group to gid (implies --user)
-r, --map-root-user map current user to root (implies --user)
-c, --map-current-user map current user to itself (implies --user)
--map-auto map users and groups automatically (implies --user)
--map-users=<outeruid>,<inneruid>,<count>
map count users from outeruid to inneruid (implies --user)
--map-groups=<outergid>,<innergid>,<count>
map count groups from outergid to innergid (implies --user)
--kill-child[=<signame>] when dying, kill the forked child (implies --fork)
defaults to SIGKILL
--mount-proc[=<dir>] mount proc filesystem first (implies --mount)
--propagation slave|shared|private|unchanged
modify mount propagation in mount namespace
--setgroups allow|deny control the setgroups syscall in user namespaces
--keep-caps retain capabilities granted in user namespaces
-R, --root=<dir> run the command with root directory set to <dir>
-w, --wd=<dir> change working directory to <dir>
-S, --setuid <uid> set uid in entered namespace
-G, --setgid <gid> set gid in entered namespace
--monotonic <offset> set clock monotonic offset (seconds) in time namespaces
--boottime <offset> set clock boottime offset (seconds) in time namespaces
-h, --help display this help
-V, --version display version
For more details see unshare(1).utmpdump
Dump UTMP and WTMP files in raw format
:~# utmpdump -h
Usage:
utmpdump [options] [filename]
Dump UTMP and WTMP files in raw format.
Options:
-f, --follow output appended data as the file grows
-r, --reverse write back dumped data into utmp file
-o, --output <file> write to file instead of standard output
-h, --help display this help
-V, --version display version
For more details see utmpdump(1).wdctl
Show hardware watchdog status
:~# wdctl -h
Usage:
wdctl [options] [<device> ...]
Show the status of the hardware watchdog.
Options:
-f, --flags <list> print selected flags only
-F, --noflags don't print information about flags
-I, --noident don't print watchdog identity information
-n, --noheadings don't print headings for flags table
-O, --oneline print all information on one line
-o, --output <list> output columns of the flags
-p, --setpretimeout <sec> set watchdog pre-timeout
-g, --setpregovernor <name> set pre-timeout governor
-r, --raw use raw output format for flags table
-T, --notimeouts don't print watchdog timeouts
-s, --settimeout <sec> set watchdog timeout
-x, --flags-only print only flags table (same as -I -T)
-h, --help display this help
-V, --version display version
No default device is available.
Available output columns:
FLAG flag name
DESCRIPTION flag description
STATUS flag status
BOOT-STATUS flag boot status
DEVICE watchdog device name
For more details see wdctl(8).whereis
Locate the binary, source, and manual page files for a command
:~# whereis -h
Usage:
whereis [options] [-BMS <dir>... -f] <name>
Locate the binary, source, and manual-page files for a command.
Options:
-b search only for binaries
-B <dirs> define binaries lookup path
-m search only for manuals and infos
-M <dirs> define man and info lookup path
-s search only for sources
-S <dirs> define sources lookup path
-f terminate <dirs> argument list
-u search for unusual entries
-l output effective lookup paths
-h, --help display this help
-V, --version display version
For more details see whereis(1).wipefs
Wipe a signature from a device
:~# wipefs -h
Usage:
wipefs [options] <device>
Wipe signatures from a device.
Options:
-a, --all wipe all magic strings (BE CAREFUL!)
-b, --backup create a signature backup in $HOME
-f, --force force erasure
-i, --noheadings don't print headings
-J, --json use JSON output format
-n, --no-act do everything except the actual write() call
-o, --offset <num> offset to erase, in bytes
-O, --output <list> COLUMNS to display (see below)
-p, --parsable print out in parsable instead of printable format
-q, --quiet suppress output messages
-t, --types <list> limit the set of filesystem, RAIDs or partition tables
--lock[=<mode>] use exclusive device lock (yes, no or nonblock)
-h, --help display this help
-V, --version display version
Arguments:
<num> arguments may be followed by the suffixes for
GiB, TiB, PiB, EiB, ZiB, and YiB (the "iB" is optional)
Available output columns:
UUID partition/filesystem UUID
LABEL filesystem LABEL
LENGTH magic string length
TYPE superblok type
OFFSET magic string offset
USAGE type description
DEVICE block device name
For more details see wipefs(8).x86_64
Change reported architecture in new program environment and/or set personality flags
:~# x86_64 -h
Usage:
x86_64 [options] [<program> [<argument>...]]
Change the reported architecture and set personality flags.
Options:
-B, --32bit turns on ADDR_LIMIT_32BIT
-F, --fdpic-funcptrs makes function pointers point to descriptors
-I, --short-inode turns on SHORT_INODE
-L, --addr-compat-layout changes the way virtual memory is allocated
-R, --addr-no-randomize disables randomization of the virtual address space
-S, --whole-seconds turns on WHOLE_SECONDS
-T, --sticky-timeouts turns on STICKY_TIMEOUTS
-X, --read-implies-exec turns on READ_IMPLIES_EXEC
-Z, --mmap-page-zero turns on MMAP_PAGE_ZERO
-3, --3gb limits the used address space to a maximum of 3 GB
--4gb ignored (for backward compatibility only)
--uname-2.6 turns on UNAME26
-v, --verbose say what options are being switched on
-h, --help display this help
-V, --version display version
For more details see setarch(8).zramctl
Set up and control zram devices
:~# zramctl -h
Usage:
zramctl [options] <device>
zramctl -r <device> [...]
zramctl [options] -f | <device> -s <size>
Set up and control zram devices.
Options:
-a, --algorithm <alg> compression algorithm to use
-b, --bytes print sizes in bytes rather than in human readable format
-f, --find find a free device
-n, --noheadings don't print headings
-o, --output <list> columns to use for status output
--output-all output all columns
--raw use raw status output format
-r, --reset reset all specified devices
-s, --size <size> device size
-t, --streams <number> number of compression streams
-h, --help display this help
-V, --version display version
Arguments:
<size> arguments may be followed by the suffixes for
GiB, TiB, PiB, EiB, ZiB, and YiB (the "iB" is optional)
<alg> specify algorithm, supported are:
lzo, lz4, lz4hc, deflate, 842 and zstd
Available output columns:
NAME zram device name
DISKSIZE limit on the uncompressed amount of data
DATA uncompressed size of stored data
COMPR compressed size of stored data
ALGORITHM the selected compression algorithm
STREAMS number of concurrent compress operations
ZERO-PAGES empty pages with no allocated memory
TOTAL all memory including allocator fragmentation and metadata overhead
MEM-LIMIT memory limit used to store compressed data
MEM-USED memory zram have been consumed to store compressed data
MIGRATED number of objects migrated by compaction
MOUNTPOINT where the device is mounted
For more details see zramctl(8).Tools commonly found on systems where humans login interactively, or are needed with non-standard system configurations.
Installed size: 366 KB
How to install: sudo apt install util-linux-extra
fincore
Count pages of file contents in core
:~# fincore -h
Usage:
fincore [options] file...
Options:
-J, --json use JSON output format
-b, --bytes print sizes in bytes rather than in human readable format
-n, --noheadings don't print headings
-o, --output <list> output columns
-r, --raw use raw output format
-h, --help display this help
-V, --version display version
Available output columns:
PAGES file data resident in memory in pages
SIZE size of the file
FILE file name
RES file data resident in memory in bytes
For more details see fincore(1).hwclock
Settings that affect the behaviour of the hwclock init script Time clocks utility
:~# hwclock -h
Usage:
hwclock [function] [option...]
Time clocks utility.
Functions:
-r, --show display the RTC time
--get display drift corrected RTC time
--set set the RTC according to --date
-s, --hctosys set the system time from the RTC
-w, --systohc set the RTC from the system time
--systz send timescale configurations to the kernel
-a, --adjust adjust the RTC to account for systematic drift
--param-get <param> display the RTC parameter
--param-set <param>=<value> set the RTC parameter
--predict predict the drifted RTC time according to --date
Options:
-u, --utc the RTC timescale is UTC
-l, --localtime the RTC timescale is Local
-f, --rtc <file> use an alternate file to /dev/rtc0
--directisa use the ISA bus instead of /dev/rtc0 access
--date <time> date/time input for --set and --predict
--delay <sec> delay used when set new RTC time
--update-drift update the RTC drift factor
--noadjfile do not use /etc/adjtime
--adjfile <file> use an alternate file to /etc/adjtime
--test dry run; implies --verbose
-v, --verbose display more details
-h, --help display this help
-V, --version display version
Arguments:
<param> is either a numeric RTC parameter value or one of these aliases:
- features: supported features (0x0)
- correction: time correction (0x1)
- bsm: backup switch mode (0x2)
See Kernel's include/uapi/linux/rtc.h for parameters and values.
<param> and <value> accept hexadecimal values if prefixed with 0x, otherwise decimal.
For more details see hwclock(8).lsfd
List file descriptors
:~# lsfd -h
Usage:
lsfd [options]
Options:
-l, --threads list in threads level
-J, --json use JSON output format
-n, --noheadings don't print headings
-o, --output <list> output columns
-r, --raw use raw output format
-u, --notruncate don't truncate text in columns
-p, --pid <pid(s)> collect information only specified processes
-Q, --filter <expr> apply display filter
--debug-filter dump the internal data structure of filter and exit
-C, --counter <name>:<expr>
define custom counter for --summary output
--dump-counters dump counter definitions
--summary[=when] print summary information (only, append, or never)
-h, --help display this help
-V, --version display version
Available output columns:
ASSOC <string> association between file and process
BLKDRV <string> block device driver name resolved by /proc/devices
CHRDRV <string> character device driver name resolved by /proc/devices
COMMAND <string> command of the process opening the file
DELETED <boolean> reachability from the file system
DEV <string> ID of device containing file
DEVTYPE <string> device type (blk, char, or nodev)
FD <number> file descriptor for the file
FLAGS <string> flags specified when opening the file
INODE <number> inode number
KTHREAD <boolean> opened by a kernel thread
MAJ:MIN <string> device ID for special, or ID of device containing file
MAPLEN <number> length of file mapping (in page)
MISCDEV <string> misc character device name resolved by /proc/misc
MNTID <number> mount id
MODE <string> access mode (rwx)
NAME <string> name of the file
NLINK <number> link count
PARTITION <string> block device name resolved by /proc/partition
PID <number> PID of the process opening the file
POS <number> file position
PROTONAME <string> protocol name
RDEV <string> device ID (if special file)
SIZE <number> file size
SOURCE <string> file system, partition, or device containing file
TID <number> thread ID of the process opening the file
TYPE <string> file type
UID <number> user ID number of the process
USER <string> user of the process
FUID <number> user ID number of the file's owner
OWNER <string> owner of the file
For more details see lsfd(1).lsirq
Utility to display kernel interrupt information
:~# lsirq -h
Usage:
lsirq [options]
Utility to display kernel interrupt information.
Options:
-J, --json use JSON output format
-P, --pairs use key="value" output format
-n, --noheadings don't print headings
-o, --output <list> define which output columns to use
-s, --sort <column> specify sort column
-S, --softirq show softirqs instead of interrupts
-h, --help display this help
-V, --version display version
Available output columns:
IRQ interrupts
TOTAL total count
NAME name
For more details see lsirq(1).util-linux-locales
This package contains the internationalization files for the util-linux package.
They are needed when you want the programs in util-linux to print their messages in other languages than English.
Installed size: 7.78 MB
How to install: sudo apt install util-linux-locales
uuid-dev
The libuuid library generates and parses 128-bit Universally Unique IDs (UUIDs). See RFC 4122 for more information.
This package contains the development environment for the uuid library.
Installed size: 113 KB
How to install: sudo apt install uuid-dev
uuid-runtime
The libuuid library generates and parses 128-bit Universally Unique IDs (UUIDs). A UUID is an identifier that is unique within the space of all such identifiers across both space and time. It can be used for multiple purposes, from tagging objects with an extremely short lifetime to reliably identifying very persistent objects across a network.
See RFC 4122 for more information.
This package contains the uuidgen program and the uuidd daemon.
The uuidd daemon is used to generate UUIDs, especially time-based UUIDs, in a secure and guaranteed-unique fashion, even in the face of large numbers of threads trying to grab UUIDs running on different CPUs. It is used by libuuid as well as the uuidgen program.
Installed size: 174 KB
How to install: sudo apt install uuid-runtime
uuidd
UUID generation daemon
:~# uuidd -h
Usage:
uuidd [options]
A daemon for generating UUIDs.
Options:
-p, --pid <path> path to pid file
-s, --socket <path> path to socket
-T, --timeout <sec> specify inactivity timeout
-k, --kill kill running daemon
-r, --random test random-based generation
-t, --time test time-based generation
-n, --uuids <num> request number of uuids
-P, --no-pid do not create pid file
-F, --no-fork do not daemonize using double-fork
-S, --socket-activation do not create listening socket
-C, --cont-clock[=<NUM>[hd]]
activate continuous clock handling
-d, --debug run in debugging mode
-q, --quiet turn on quiet mode
-h, --help display this help
-V, --version display version
For more details see uuidd(8).uuidgen
Create a new UUID value
:~# uuidgen -h
Usage:
uuidgen [options]
Create a new UUID value.
Options:
-r, --random generate random-based uuid
-t, --time generate time-based uuid
-n, --namespace ns generate hash-based uuid in this namespace
available namespaces: @dns @url @oid @x500
-N, --name name generate hash-based uuid from this name
-m, --md5 generate md5 hash
-s, --sha1 generate sha1 hash
-x, --hex interpret name as hex string
-h, --help display this help
-V, --version display version
For more details see uuidgen(1).uuidparse
A utility to parse unique identifiers
:~# uuidparse -h
Usage:
uuidparse [options] <uuid ...>
Options:
-J, --json use JSON output format
-n, --noheadings don't print headings
-o, --output <list> COLUMNS to display (see below)
-r, --raw use the raw output format
-h, --help display this help
-V, --version display version
Available output columns:
UUID unique identifier
VARIANT variant name
TYPE type name
TIME timestamp
For more details see uuidparse(1).Updated on: 2023-Mar-08
Last updated