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_datetime
Next: 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]