coreutils: Multi-call programwc: Print newline, word, and byte countssum: Print checksum and block countscksum: Print CRC checksum and byte countsb2sum: Print or check BLAKE2 digestsmd5sum: Print or check MD5 digestssha1sum: Print or check SHA-1 digestslink: Make a hard link via the link syscallln: Make links between filesmkdir: Make directoriesmkfifo: Make FIFOs (named pipes)mknod: Make block or character special filesreadlink: Print value of a symlink or canonical file namermdir: Remove empty directoriesunlink: Remove files via the unlink syscallchroot: Run a command with a different root directoryenv: Run a command in a modified environmentnice: Run a command with modified nicenessnohup: Run a command immune to hangupsstdbuf: Run a command with modified I/O stream bufferingtimeout: Run a command with a time limitparse_datetimeNext: Introduction, Up: (dir) [Contents][Index]
This manual documents version 8.28 of the GNU core utilities, including the standard programs for text and file manipulation.
Copyright © 1994-2017 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”.
| • Introduction: | Caveats, overview, and authors | |
| • Common options: | Common options | |
| • Output of entire files: | cat tac nl od base32 base64 | |
| • 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 | |
| • Disk 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 | |
| • 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 | |
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 | |
| ||
| • 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 | |
| ||
| • Character sets: | Specifying sets 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
| |
| ||
| • Which files are listed: | Which files are listed | |
| • What information is listed: | What information is listed | |
| • Sorting the output: | Sorting the output | |
| • Details about version sort: | More details about version sort | |
| • 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 | |
Disk usage | ||
| • df invocation: | Report file system disk 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 | |
| ||
| • 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 | |
| ||
| • 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 | |
| ||
| • 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 | |
| ||
| • 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: | 19 Dec 1994 | |
| • Time of day items: | 9:20pm | |
| • Time zone items: | EST, PDT, UTC, … | |
| • Combined date and time of day items: | 1972-09-24T20:02:00,000000-0500 | |
| • Day of week items: | Monday and others | |
| • Relative items in date strings: | next tuesday, 2 years ago | |
| • Pure numbers in date strings: | 19931219, 1440 | |
| • Seconds since the Epoch: | @1078100502 | |
| • Specifying time zone rules: | TZ="America/New_York", TZ="UTC0" | |
| • Authors of parse_datetime: | Bellovin, Eggert, Salz, Berets, et al. | |
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 | |
Next: Introduction, Up: (dir) [Contents][Index]