Software:cut (Unix)
Original author(s) | AT&T Bell Laboratories |
---|---|
Developer(s) | Various open-source and commercial developers |
Initial release | February 1985 |
Operating system | Unix, Unix-like, IBM i |
Platform | Cross-platform |
Type | Command |
License | coreutils: GPLv3+ |
In computing, cut
is a command line utility on Unix and Unix-like operating systems which is used to extract sections from each line of input — usually from a file. It is currently part of the GNU coreutils package and the BSD Base System.
Extraction of line segments can typically be done by bytes (-b
), characters (-c
), or fields (-f
) separated by a delimiter (-d
— the tab character by default). A range must be provided in each case which consists of one of N
, N-M,
N-
(N
to the end of the line), or -M
(beginning of the line to M
), where N and M are counted from 1 (there is no zeroth value). Since version 6, an error is thrown if you include a zeroth value. Prior to this the value was ignored and assumed to be 1.
History
The original Bell Labs version was written by Gottfried W. R. Luderer.[1][2] cut
is part of the X/Open Portability Guide since issue 2 of 1987. It was inherited into the first version of POSIX.1 and the Single Unix Specification.[3] It first appeared in AT&T System III UNIX in 1982.[4]
The version of cut
bundled in GNU coreutils was written by David M. Ihnat, David MacKenzie, and Jim Meyering.[5] The command is available as a separate package for Microsoft Windows as part of the UnxUtils collection of native Win32 ports of common GNU Unix-like utilities.[6] The cut command has also been ported to the IBM i operating system.[7]
Examples
Assuming a file named "file
" containing the lines:
foo:bar:baz:qux:quux one:two:three:four:five:six:seven alpha:beta:gamma:delta:epsilon:zeta:eta:theta:iota:kappa:lambda:mu the quick brown fox jumps over the lazy dog
To output the fourth through tenth characters of each line:
$ cut -c 4-10 file :bar:ba :two:th ha:beta quick
To output the fifth field through the end of the line of each line using the colon character as the field delimiter:
$ cut -d ":" -f 5- file quux five:six:seven epsilon:zeta:eta:theta:iota:kappa:lambda:mu the quick brown fox jumps over the lazy dog
(note that because the colon character is not found in the last line the entire line is shown)
Option -d
specifies a single character delimiter (in the example above it is a colon) which serves as field separator. Option -f
which specifies range of fields included in the output (here fields range from five till the end). Option -d
presupposes usage of option -f
.
To output the third field of each line using space as the field delimiter:
$ cut -d " " -f 3 file foo:bar:baz:qux:quux one:two:three:four:five:six:seven alpha:beta:gamma:delta:epsilon:zeta:eta:theta:iota:kappa:lambda:mu brown
(Note that because the space character is not found in the first three lines these entire lines are shown.)
To separate two words having any delimiter:
$ line=process.processid $ cut -d "." -f1 <<< $line process $ cut -d "." -f2 <<< $line processid
Syntax
cut [-b list] [-c list] [-f list] [-n] [-d delim] [-s] [file]
Flags which may be used include:
- -b
- Bytes; a list following -b specifies a range of bytes which will be returned, e.g.
cut -b1-66
would return the first 66 bytes of a line. NB If used in conjunction with -n, no multi-byte characters will be split. NNB. -b will only work on input lines of less than 1023 bytes - -c
- Characters; a list following -c specifies a range of characters which will be returned, e.g.
cut -c1-66
would return the first 66 characters of a line - -f
- Specifies a field list, separated by a delimiter
- list
- A comma separated or blank separated list of integer denoted fields, incrementally ordered. The - indicator may be supplied as shorthand to allow inclusion of ranges of fields e.g. 4-6 for ranges 4–6 or 5- as shorthand for field 5 to the end, etc.
- -n
- Used in combination with -b suppresses splits of multi-byte characters
- -d
- Delimiter; the character immediately following the -d option is the field delimiter for use in conjunction with the -f option; the default delimiter is tab. Space and other characters with special meanings within the context of the shell in use must be enquoted or escaped as necessary.
- -s
- Bypasses lines which contain no field delimiters when -f is specified, unless otherwise indicated.
- file
- The file (and accompanying path if necessary) to process as input. If no file is specified then standard input will be used.
See also
References
- ↑ "cut(1) - OpenBSD manual pages". https://man.openbsd.org/cut.1.
- ↑ "[TUHS A portrait of cut(1)"]. 15 January 2020. https://www.tuhs.org/pipermail/tuhs/2020-January/019955.html.
- ↑ The Single UNIX Specification, Issue 7 from The Open Group – Commands & Utilities Reference,
- ↑ FreeBSD General Commands Manual –
- ↑ Linux General Commands Manual –
- ↑ "Native Win32 ports of some GNU utilities". http://unxutils.sourceforge.net/.
- ↑ IBM. "IBM System i Version 7.2 Programming Qshell" (in en). https://www.ibm.com/support/knowledgecenter/ssw_ibm_i_74/rzahz/rzahzpdf.pdf?view=kc.
External links
- The Single UNIX Specification, Issue 7 from The Open Group – Commands & Utilities Reference,
- Softpanorama cut page.
- Cut out selected fields of each line of a file A portrait of cut(1) and its historical background.
Original source: https://en.wikipedia.org/wiki/Cut (Unix).
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