cut(1)
NAME
cut − cut out selected fields of each line of a file
SYNTAX
cut −clist [file1 file2 ...]
cut −flist [−dchar] [−s] [file1 file2 ...]
DESCRIPTION
Use the cut command to cut out columns from a table or fields from each line of a file; in data base parlance, it implements the projection of a relation. 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). The cut command can be used as a filter. If no files are given, the standard input is used.
Use grep(1) to make horizontal “cuts” (by context) through a file, or paste(1) to put files together column-wise (that is, horizontally). To reorder columns in a table, use cut and paste.
The meanings of the options are:
list A comma-separated list of integer field numbers (in increasing order), with optional − to indicate ranges as in the −o option of nroff/troff for page ranges; for example, 1,4,7; 1−3,8; −5,10 (short for 1−5,10); or 3− (short for third through last field).
−clist The list following −c (no space) specifies character positions (for example, −c1−72 would pass the first 72 characters of each line).
−flist The list following −f is a list of fields assumed to be separated in the file by a delimiter character (see −d ); for example, −f1,7 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.
−dchar 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.
−s Suppresses lines with no delimiter characters in case of −f option. Unless specified, lines with no delimiters will be passed through untouched.
Either the −c or −f option must be specified.
EXAMPLES
cut −d: −f1,5 /etc/passwd mapping of user IDs to names
name=`who am i | cut −f1 −d" "` to set name to current login name.
DIAGNOSTICS
line too long A line can have no more than 511 characters or fields.
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.