File: coreutils.info, Node: Top, Next: Introduction, Up: (dir) 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 Conditions * 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’ Redirection * 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. Delaying * 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年11月14日T21:02:42,000000-0500’ * 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