SORT(1) BSD SORT(1)
NAME
sort - sort or merge files
SYNOPSIS
sort [ options ] [ files ]
DESCRIPTION
sort sorts lines of all the named files together and writes the result on
the standard output. A dash (-) used as a filename means the standard
input. If you specify no input files, sort uses the standard input.
The default sort key is an entire line. Default ordering is
lexicographic by bytes in machine collating sequence. The ordering is
affected globally by the following options, one or more of which may
appear.
OPTIONS
-b Ignore leading blanks (spaces and tabs) in field
comparisons.
-d Use dictionary order, making only letters, digits, and
blanks significant in comparisons.
-f Fold uppercase letters onto lowercase.
-i Ignore characters outside the ASCII range 040-0176 in
non-numeric comparisons.
-n Sort an initial numeric string (consisting of optional
blanks, optional minus sign, and zero or more digits with
optional decimal point) by arithmetic value. This option
implies option -b.
-r Reverse the sense of comparisons.
-tx Specify x as the tab character separating fields.
+pos1 [-pos2] Restrict a sort key to a field beginning at pos1 and
ending just before pos2. Both pos1 and pos2 have the form
m.n, optionally followed by one or more of the flags
-bdfinr, where m specifies the number of fields to skip
from the beginning of the line and n specifies the number
of characters to skip further.
If any flags are present they override all the global
ordering options for this key. If the -b option is in
effect, n is counted from the first nonblank in the field;
-b is attached independently to pos2. A missing .n means
.0; a missing -pos2 means the end of the line. Under the
-tx option, fields are strings separated by x; otherwise
fields are non-empty non-blank strings separated by
blanks.
When there are multiple sort keys, later keys are compared
only after all earlier keys compare equal. Lines that
otherwise compare equal are ordered with all bytes
significant.
-c Ensure that the input file is sorted according to the
ordering rules; give no output unless the file is out of
sort.
-m Merge only; the input files are already sorted.
-o name Use name as the output file instead of the standard
output. This file may be the same as one of the inputs.
-T directory Use directory as the name of a directory in which
temporary files should be made.
-u Suppress all but one line in each set of equal lines.
Ignored bytes and bytes outside keys do not participate in
this comparison.
EXAMPLES
To print in alphabetical order all the unique spellings in a list of
words, with capitalized words distinguished from uncapitalized, use
sort -u +0f +0 list
To print the password file sorted by user ID number (the third colon-
separated field as described in passwd(5)), use
sort -t: +2n /etc/passwd
To print the first instance of each month in an already sorted file of
month/day entries, use the command line shown below. The options -um
with just one input file make the choice of a unique representative from
a set of equal lines predictable.
sort -um +0 -1 dates
FILES
/usr/tmp/stm*, /tmp/* first and second tries for temporary files
DIAGNOSTICS
Comments and exits with nonzero status for various trouble conditions and
for disorder discovered under option -c.
BUGS
Very long lines are silently truncated.
SEE ALSO
uniq(1), comm(1), rev(1), join(1)