cut(C)

cut -- cut out selected fields of each line of a file

Syntax

cut -b list [ -n ] [ file ... ]

cut -c list [ file ... ]

cut -f list [ -d char ] [ -s ] [ -wF | -W ] [ file ... ]

Description

Use cut to cut out columns from a table or fields from each line of one or more files. The fields as specified by list can be fixed length, that is, character positions as on a punched card (-c option), or the length can vary from line to line and be marked with a field delimiter character like Tab (-f option). If no files are specified, cut reads from the standard input.

cut can be used as a filter.

The list is a comma-separated list of integers (in increasing order). It can be tab or blank-separated if it is enclosed in quotes. A dash (-) can be used to indicate ranges, for example:

1,3,7: fields 1, 3, and 7
2-4,8: fields 2, 3, 4, and 8
-4,10: equivalent to 1-4,10
2-: equivalent to the second through last field

cut understands the following options:

-b list: list specifies byte positions. For example, -b 1-100 cuts the first 100 bytes of each line. Each selected byte will be output unless explicitly suppressed by the -n option).
-c list: list specifies character positions. For example, -c 1-72 would keep the first 72 characters of each line.
-f list: list specifies fields assumed to be separated in the file by a delimiter character (see -d). For example, -f 1,7 copies the first and seventh field only. Lines with no field delimiters will be passed through intact (useful for table subheadings), unless -s is specified.
-d char: The character following -d is the field delimiter (-f option only). Default is Tab. Space or other characters with special meaning to the shell must be quoted.
-n: Do not split characters. Used in conjunction with the -b option as in the following example:

cut -b 1-100 -n file
Here 1 is the low byte and 100 is the high byte. If the low byte is not the first byte of a character, its value will be decremented by 1 so that the first byte of a character is selected. Similarly, if the specified high byte is not the last byte of a character, its value will be decremented by 1 so that the selected byte becomes the last byte of the character prior to the character selected on the command line.
-s: If the -f option is used, -s suppresses lines with no delimiter characters. Unless specified, lines with no delimiters will be passed through untouched.
-w: If the -f option is used, -w treats any whitespace as a delimiter.
-F: If the -f option is used, -F folds adjacent delimiters together.
-s: Convenience abbreviation for -wF.

One of the options -b, -c or -f must be specified.

Exit values

cut returns a value of 0 if it executes successfully. A failure to open an input file results in a return status of 1; all other fatal errors result in a return status of 2.

Diagnostics

The following error messages may be displayed:

bad list for c / f option: Missing -c or -f option or incorrectly specified list. No error occurs if a line has fewer fields than the list calls for.
no fields: The list is empty.

Examples

Map user IDs to names:

cut -d: -f 1,3 /etc/passwd

Set name to current login name:

name=`who am i | cut -f1 -d" "`

Limitations

Use grep(C) to make horizontal ``cuts'' (by context) through a file, or paste(C) to put files together horizontally.

To reorder columns in a table, use cut and paste.

Standards conformance

cut is conformant with:

ISO/IEC DIS 99452:1992, Information technology Portable Operating System Interface (POSIX) Part 2: Shell and Utilities (IEEE Std 1003.21992);
AT&T SVID Issue 2;
X/Open CAE Specification, Commands and Utilities, Issue 4, 1992.