GNU Core-utils

@insertcopying

1. Introduction		Caveats, overview, and authors.
2. Common options
3. Output of entire files		cat tac nl od
4. Formatting file contents		fmt pr fold
5. Output of parts of files		head tail split csplit
6. Summarizing files		wc sum cksum md5sum
7. Operating on sorted files		sort uniq comm ptx tsort
8. Operating on fields within a line		cut paste join
9. Operating on characters		tr expand unexpand
10. Directory listing		ls dir vdir d v dircolors
11. Basic operations		cp dd install mv rm shred
12. Special file types		ln mkdir rmdir mkfifo mknod
13. Changing file attributes		chgrp chmod chown touch
14. Disk usage		df du stat sync
15. Printing text		echo printf yes
16. Conditions		false true test expr
17. Redirection		tee
18. File name manipulation		dirname basename pathchk
19. Working context		pwd stty printenv tty
20. User information		id logname whoami groups users who
21. System context		date uname hostname
22. Modified command invocation		chroot env nice nohup su
23. Process control		kill
24. Delaying		sleep
25. Numeric operations		factor seq
26. File permissions		Access modes.
27. Date input formats		Specifying date strings.
28. Opening the Software Toolbox		The software tools philosophy.
A. GNU Free Documentation License		The license for this documentation.
Index		General index.

 -- The Detailed Node Listing ---

Common Options

2.1 Backup options
2.2 Block size
2.3 Target directory
2.4 Trailing slashes
2.5 Standards conformance

Output of entire files

3.1 cat: Concatenate and write files		Concatenate and write files.
3.2 tac: Concatenate and write files in reverse		Concatenate and write files in reverse.
3.3 nl: Number lines and write files		Number lines and write files.
3.4 od: Write files in octal or other formats		Write files in octal or other formats.

Formatting file contents

4.1 fmt: Reformat paragraph text		Reformat paragraph text.
4.2 pr: Paginate or columnate files for printing		Paginate or columnate files for printing.
4.3 fold: Wrap input lines to fit in specified width		Wrap input lines to fit in specified width.

Output of parts of files

5.1 head: Output the first part of files		Output the first part of files.
5.2 tail: Output the last part of files		Output the last part of files.
5.3 split: Split a file into fixed-size pieces		Split a file into fixed-size pieces.
5.4 csplit: Split a file into context-determined pieces		Split a file into context-determined pieces.

Summarizing files

6.1 wc: Print byte, word, and line counts		Print byte, word, and line counts.
6.2 sum: Print checksum and block counts		Print checksum and block counts.
6.3 cksum: Print CRC checksum and byte counts		Print CRC checksum and byte counts.
6.4 md5sum: Print or check message-digests		Print or check message-digests.

Operating on sorted files

7.1 sort: Sort text files		Sort text files.
7.2 uniq: Uniquify files		Uniquify files.
7.3 comm: Compare two sorted files line by line		Compare two sorted files line by line.
7.6 ptx: Produce permuted indexes		Produce a permuted index of file contents.
7.4 tsort: Topological sort		Topological sort.

ptx: Produce permuted indexes

7.6.1 General options		Options which affect general program behavior.
7.6.2 Charset selection		Underlying character set considerations.
7.6.3 Word selection and input processing		Input fields, contexts, and keyword selection.
7.6.4 Output formatting		Types of output format, and sizing the fields.
7.6.5 The GNU extensions to ptx

Operating on fields within a line

8.1 cut: Print selected parts of lines		Print selected parts of lines.
8.2 paste: Merge lines of files		Merge lines of files.
8.3 join: Join lines on a common field		Join lines on a common field.

Operating on characters

9.1 tr: Translate, squeeze, and/or delete characters		Translate, squeeze, and/or delete characters.
9.2 expand: Convert tabs to spaces		Convert tabs to spaces.
9.3 unexpand: Convert spaces to tabs		Convert spaces to tabs.

tr: Translate, squeeze, and/or delete characters

9.1.1 Specifying sets of characters
9.1.2 Translating		Changing one characters to another.
9.1.3 Squeezing repeats and deleting
9.1.4 Warning messages

Directory listing

10.1 ls: List directory contents		List directory contents
10.2 dir: Briefly list directory contents		Briefly list directory contents
10.3 vdir: Verbosely list directory contents		Verbosely list directory contents
10.4 dircolors: Color setup for ls		Color setup for ls

ls:  List directory contents

10.1.1 Which files are listed
10.1.2 What information is listed
10.1.3 Sorting the output
10.1.4 More details about version sort
10.1.5 General output formatting
10.1.7 Formatting the file names

Basic operations

11.1 cp: Copy files and directories		Copy files and directories
11.2 dd: Convert and copy a file		Convert and copy a file
11.3 install: Copy files and set attributes		Copy files and set attributes
11.4 mv: Move (rename) files		Move (rename) files
11.5 rm: Remove files or directories		Remove files or directories
11.6 shred: Remove files more securely		Remove files more securely

Special file types

12.1 link: Make a hard link via the link syscall		Make a hard link via the link syscall
12.2 ln: Make links between files		Make links between files
12.3 mkdir: Make directories		Make directories
12.4 mkfifo: Make FIFOs (named pipes)		Make FIFOs (named pipes)
12.5 mknod: Make block or character special files		Make block or character special files
12.6 rmdir: Remove empty directories		Remove empty directories
12.7 unlink: Remove files via the unlink syscall		Remove files via unlink syscall

Changing file attributes

13.1 chown: Change file owner and group		Change file owner and group
13.2 chgrp: Change group ownership		Change group ownership
13.3 chmod: Change access permissions		Change access permissions
13.4 touch: Change file timestamps		Change file timestamps

Disk usage

14.1 df: Report filesystem disk space usage		Report filesystem disk space usage
14.2 du: Estimate file space usage		Estimate file space usage
14.3 stat: Report file or filesystem status		Report file or filesystem status
14.4 sync: Synchronize data on disk with memory		Synchronize data on disk with memory

Printing text

15.1 echo: Print a line of text		Print a line of text
15.2 printf: Format and print data		Format and print data
15.3 yes: Print a string until interrupted		Print a string until interrupted

Conditions

16.1 false: Do nothing, unsuccessfully		Do nothing, unsuccessfully
16.2 true: Do nothing, successfully		Do nothing, successfully
16.3 test: Check file types and compare values		Check file types and compare values
16.4 expr: Evaluate expressions		Evaluate expressions

test: Check file types and compare values

16.3.1 File type tests
16.3.2 Access permission tests
16.3.3 File characteristic tests
16.3.4 String tests
16.3.5 Numeric tests

expr: Evaluate expression

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

Redirection

17.1 tee: Redirect output to multiple files

Redirect output to multiple files

File name manipulation

18.1 basename: Strip directory and suffix from a file name		Strip directory and suffix from a file name
18.2 dirname: Strip non-directory suffix from a file name		Strip non-directory suffix from a file name
18.3 pathchk: Check file name portability		Check file name portability

Working context

19.1 pwd: Print working directory		Print working directory
19.2 stty: Print or change terminal characteristics		Print or change terminal characteristics
19.3 printenv: Print all or some environment variables		Print all or some environment variables
19.4 tty: Print file name of terminal on standard input		Print file name of terminal on standard input

stty: Print or change terminal characteristics

19.2.1 Control settings
19.2.2 Input settings
19.2.3 Output settings
19.2.4 Local settings
19.2.5 Combination settings
19.2.6 Special characters
19.2.7 Special settings

User information

20.1 id: Print real and effective uid and gid		Print real and effective uid and gid
20.2 logname: Print current login name		Print current login name
20.3 whoami: Print effective user id		Print effective user id
20.4 groups: Print group names a user is in		Print group names a user is in
20.5 users: Print login names of users currently logged in		Print login names of users currently logged in
20.6 who: Print who is currently logged in		Print who is currently logged in

System context

21.1 date: Print or set system date and time		Print or set system date and time
21.2 uname: Print system information		Print system information
21.3 hostname: Print or set system name		Print or set system name
21.4 hostid: Print numeric host identifier.		Print numeric host identifier.

date: Print or set system date and time

21.1.1 Time directives
21.1.2 Date directives
21.1.3 Literal directives
21.1.4 Padding
21.1.5 Setting the time
21.1.6 Options for date
21.1.7 Examples of date

Modified command invocation

22.1 chroot: Run a command with a different root directory		Run a command with a different root directory
22.2 env: Run a command in a modified environment		Run a command in a modified environment
22.3 nice: Run a command with modified scheduling priority		Run a command with modified scheduling priority
22.4 nohup: Run a command immune to hangups		Run a command immune to hangups
22.5 su: Run a command with substitute user and group id		Run a command with substitute user and group id

Process control

23.1 kill: Send a signal to processes

Sending a signal to processes.

Delaying

24.1 sleep: Delay for a specified time

Delay for a specified time

Numeric operations

25.1 factor: Print prime factors		Print prime factors
25.2 seq: Print numeric sequences		Print numeric sequences

File permissions

26.1 Structure of File Permissions
26.2 Symbolic Modes		Mnemonic permissions representation
26.3 Numeric Modes		Permissions as octal numbers

Date input formats

27.1 General date syntax
27.2 Calendar date items
27.3 Time of day items
27.4 Time zone items
27.5 Day of week items
27.6 Relative items in date strings
27.7 Pure numbers in date strings
27.8 Authors of getdate

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

GNU Free Documentation License

ADDENDUM: How to use this License for your documents