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GNU Coreutils

This manual documents version 9.3 of the GNU core utilities, including
the standard programs for text and file manipulation.

   Copyright © 1994–2023 Free Software Foundation, Inc.

     Permission is granted to copy, distribute and/or modify this
     document under the terms of the GNU Free Documentation License,
     Version 1.3 or any later version published by the Free Software
     Foundation; with no Invariant Sections, with no Front-Cover Texts,
     and with no Back-Cover Texts.  A copy of the license is included in
     the section entitled “GNU Free Documentation License”.

* Menu:

* Introduction::                 Caveats, overview, and authors
* Common options::               Common options
* Output of entire files::       cat tac nl od base32 base64 basenc
* Formatting file contents::     fmt pr fold
* Output of parts of files::     head tail split csplit
* Summarizing files::            wc sum cksum b2sum md5sum sha1sum sha2
* Operating on sorted files::    sort shuf uniq comm ptx tsort
* Operating on fields::          cut paste join
* Operating on characters::      tr expand unexpand
* Directory listing::            ls dir vdir dircolors
* Basic operations::             cp dd install mv rm shred
* Special file types::         mkdir rmdir unlink mkfifo mknod ln link readlink
* Changing file attributes::     chgrp chmod chown touch
* File space usage::             df du stat sync truncate
* Printing text::                echo printf yes
* Conditions::                   false true test expr
* Redirection::                  tee
* File name manipulation::       dirname basename pathchk mktemp realpath
* Working context::              pwd stty printenv tty
* User information::             id logname whoami groups users who
* System context::               date arch nproc uname hostname hostid uptime
* SELinux context::              chcon runcon
* Modified command invocation::  chroot env nice nohup stdbuf timeout
* Process control::              kill
* Delaying::                     sleep
* Numeric operations::           factor numfmt seq
* File permissions::             Access modes
* File timestamps::              File timestamp issues
* Date input formats::           Specifying date strings
* Version sort ordering::        Details on version-sort algorithm
* Opening the software toolbox:: The software tools philosophy
* GNU Free Documentation License:: Copying and sharing this manual
* Concept index::                General index

 — The Detailed Node Listing —

Common Options

* Exit status::                  Indicating program success or failure
* Backup options::               Backup options
* Block size::                   Block size
* Floating point::               Floating point number representation
* Signal specifications::        Specifying signals
* Disambiguating names and IDs:: chgrp, chown, chroot, id: user and group syntax
* Random sources::               Sources of random data
* Target directory::             Target directory
* Trailing slashes::             Trailing slashes
* Traversing symlinks::          Traversing symlinks to directories
* Treating / specially::         Treating / specially
* Standards conformance::        Standards conformance
* Multi-call invocation::        Multi-call program invocation

Output of entire files

* cat invocation::               Concatenate and write files
* tac invocation::               Concatenate and write files in reverse
* nl invocation::                Number lines and write files
* od invocation::                Write files in octal or other formats
* base32 invocation::            Transform data into printable data
* base64 invocation::            Transform data into printable data
* basenc invocation::            Transform data into printable data

Formatting file contents

* fmt invocation::               Reformat paragraph text
* pr invocation::                Paginate or columnate files for printing
* fold invocation::              Wrap input lines to fit in specified width

Output of parts of files

* head invocation::              Output the first part of files
* tail invocation::              Output the last part of files
* split invocation::             Split a file into fixed-size pieces
* csplit invocation::            Split a file into context-determined pieces

Summarizing files

* wc invocation::                Print newline, word, and byte counts
* sum invocation::               Print checksum and block counts
* cksum invocation::             Print CRC checksum and byte counts
* b2sum invocation::             Print or check BLAKE2 digests
* md5sum invocation::            Print or check MD5 digests
* sha1sum invocation::           Print or check SHA-1 digests
* sha2 utilities::               Print or check SHA-2 digests

Operating on sorted files

* sort invocation::              Sort text files
* shuf invocation::              Shuffle text files
* uniq invocation::              Uniquify files
* comm invocation::              Compare two sorted files line by line
* ptx invocation::               Produce a permuted index of file contents
* tsort invocation::             Topological sort

‘ptx’: Produce permuted indexes

* General options in ptx::       Options which affect general program behavior
* Charset selection in ptx::     Underlying character set considerations
* Input processing in ptx::      Input fields, contexts, and keyword selection
* Output formatting in ptx::     Types of output format, and sizing the fields
* Compatibility in ptx::         The GNU extensions to ‘ptx’

Operating on fields

* cut invocation::               Print selected parts of lines
* paste invocation::             Merge lines of files
* join invocation::              Join lines on a common field

Operating on characters

* tr invocation::                Translate, squeeze, and/or delete characters
* expand invocation::            Convert tabs to spaces
* unexpand invocation::          Convert spaces to tabs

‘tr’: Translate, squeeze, and/or delete characters

* Character arrays::             Specifying arrays of characters
* Translating::                  Changing one set of characters to another
* Squeezing and deleting::       Removing characters

Directory listing

* ls invocation::                List directory contents
* dir invocation::               Briefly list directory contents
* vdir invocation::              Verbosely list directory contents
* dircolors invocation::         Color setup for ‘ls’

‘ls’:  List directory contents

* Which files are listed::       Which files are listed
* What information is listed::   What information is listed
* Sorting the output::           Sorting the output
* General output formatting::    General output formatting
* Formatting the file names::    Formatting the file names

Basic operations

* cp invocation::                Copy files and directories
* dd invocation::                Convert and copy a file
* install invocation::           Copy files and set attributes
* mv invocation::                Move (rename) files
* rm invocation::                Remove files or directories
* shred invocation::             Remove files more securely

Special file types

* link invocation::              Make a hard link via the link syscall
* ln invocation::                Make links between files
* mkdir invocation::             Make directories
* mkfifo invocation::            Make FIFOs (named pipes)
* mknod invocation::             Make block or character special files
* readlink invocation::          Print value of a symlink or canonical file name
* rmdir invocation::             Remove empty directories
* unlink invocation::            Remove files via unlink syscall

Changing file attributes

* chown invocation::             Change file owner and group
* chgrp invocation::             Change group ownership
* chmod invocation::             Change access permissions
* touch invocation::             Change file timestamps

File space usage

* df invocation::                Report file system space usage
* du invocation::                Estimate file space usage
* stat invocation::              Report file or file system status
* sync invocation::              Synchronize cached writes to persistent storage
* truncate invocation::          Shrink or extend the size of a file

Printing text

* echo invocation::              Print a line of text
* printf invocation::            Format and print data
* yes invocation::               Print a string until interrupted


* false invocation::             Do nothing, unsuccessfully
* true invocation::              Do nothing, successfully
* test invocation::              Check file types and compare values
* expr invocation::              Evaluate expressions

‘test’: Check file types and compare values

* File type tests::              File type tests
* Access permission tests::      Access permission tests
* File characteristic tests::    File characteristic tests
* String tests::                 String tests
* Numeric tests::                Numeric tests

‘expr’: Evaluate expression

* String expressions::           ‘+ : match substr index length’
* Numeric expressions::          ‘+ - * / %’
* Relations for expr::           ‘| & < <= = == != >= >’
* Examples of expr::             Examples of using ‘expr’


* tee invocation::               Redirect output to multiple files or processes

File name manipulation

* basename invocation::          Strip directory and suffix from a file name
* dirname invocation::           Strip last file name component
* pathchk invocation::           Check file name validity and portability
* mktemp invocation::            Create temporary file or directory
* realpath invocation::          Print resolved file names

Working context

* pwd invocation::               Print working directory
* stty invocation::              Print or change terminal characteristics
* printenv invocation::          Print all or some environment variables
* tty invocation::               Print file name of terminal on standard input

‘stty’: Print or change terminal characteristics

* Control::                      Control settings
* Input::                        Input settings
* Output::                       Output settings
* Local::                        Local settings
* Combination::                  Combination settings
* Characters::                   Special characters
* Special::                      Special settings

User information

* id invocation::                Print user identity
* logname invocation::           Print current login name
* whoami invocation::            Print effective user ID
* groups invocation::            Print group names a user is in
* users invocation::             Print login names of users currently logged in
* who invocation::               Print who is currently logged in

System context

* arch invocation::              Print machine hardware name
* date invocation::              Print or set system date and time
* nproc invocation::             Print the number of processors
* uname invocation::             Print system information
* hostname invocation::          Print or set system name
* hostid invocation::            Print numeric host identifier
* uptime invocation::            Print system uptime and load

‘date’: Print or set system date and time

* Time conversion specifiers::   %[HIklMNpPrRsSTXzZ]
* Date conversion specifiers::   %[aAbBcCdDeFgGhjmuUVwWxyY]
* Literal conversion specifiers:: %[%nt]
* Padding and other flags::      Pad with zeros, spaces, etc.
* Setting the time::             Changing the system clock
* Options for date::             Instead of the current time
* Date input formats::           Specifying date strings
* Examples of date::             Examples

SELinux context

* chcon invocation::             Change SELinux context of file
* runcon invocation::            Run a command in specified SELinux context

Modified command invocation

* chroot invocation::            Run a command with a different root directory
* env invocation::               Run a command in a modified environment
* nice invocation::              Run a command with modified niceness
* nohup invocation::             Run a command immune to hangups
* stdbuf invocation::            Run a command with modified I/O buffering
* timeout invocation::           Run a command with a time limit

Process control

* kill invocation::              Sending a signal to processes.


* sleep invocation::             Delay for a specified time

Numeric operations

* factor invocation::            Print prime factors
* numfmt invocation::            Reformat numbers
* seq invocation::               Print numeric sequences

File timestamps

* File timestamps::              File timestamp issues

File permissions

* Mode Structure::               Structure of file mode bits
* Symbolic Modes::               Mnemonic representation of file mode bits
* Numeric Modes::                File mode bits as octal numbers
* Directory Setuid and Setgid::  Set-user-ID and set-group-ID on directories

Date input formats

* General date syntax::          Common rules
* Calendar date items::          ‘14 Nov 2022’
* Time of day items::            ‘9:02pm’
* Time zone items::              ‘UTC’, ‘-0700’, ‘+0900’, ...
* Combined date and time of day items:: ‘2022-11-14T21:02:42,000000-0500’
* Day of week items::            ‘Monday’ and others
* Relative items in date strings:: ‘next tuesday, 2 years ago’
* Pure numbers in date strings:: ‘20221114’, ‘2102’
* Seconds since the Epoch::      ‘@1668477762’
* Specifying time zone rules::   ‘TZ="America/New_York"’, ‘TZ="UTC0"’
* Authors of parse_datetime::    Bellovin, Eggert, Salz, Berets, et al.

Version sorting order

* Version sort overview::
* Version sort implementation::
* Differences from Debian version sort::
* Advanced version sort topics::

Opening the software toolbox

* Toolbox introduction::         Toolbox introduction
* I/O redirection::              I/O redirection
* The who command::              The ‘who’ command
* The cut command::              The ‘cut’ command
* The sort command::             The ‘sort’ command
* The uniq command::             The ‘uniq’ command
* Putting the tools together::   Putting the tools together

Copying This Manual

* GNU Free Documentation License::     Copying and sharing this manual

© 2000-2023
Individual documents may contain additional copyright information.