SORT(1)
NAME
sort − sort or merge files
USAGE
sort [ −cmubdfinrtx ] [ +pos1 [ −pos2 ] ] ... [ −o name ] [ −T directory ]
[ name ] ...
DESCRIPTION
Sort arranges lines of all the named files together and writes the result on the standard output. If you do not specify 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 options listed below globally affect the ordering. You may use several options on a command line.
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, an optional minus sign, and zero or more digits with an optional decimal point, by arithmetic value. This option implies the −b option.
−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. Pos1 and pos2 each have the form m.n, optionally followed by one or more of the flags −bdfinr, where m tells a number of fields to skip from the beginning of the line and n tells a 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 nonempty, nonblank 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 name of an output file instead of the standard output. This file may be the same as one of the inputs.
−Tdirectory 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
The example immediately following shows you how to print, in alphabetical order, all the unique spellings in a list of words. Capitalized words are different from uncapitalized.
sort −u +0f +0 list
The next example shows how to print the password file sorted by user ID number (the third colon-separated field). Refer to passwd (5) for more information about the password file.
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 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
CAUTIONS
Sort silently truncates very long lines.
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.