sort - sort and/or merge files
sort [
-cmuMbdfinrwtx ] [
+pos1 [
-pos2 ] ... ] ... [
-k pos1 [
,pos2 ] ] ...
[
-o output ] [
-T dir ... ] [
option ... ] [
file ... ]
Sort sorts lines of all the
files together and writes the result
on the standard output. If no input files are named, the standard input is
sorted.
The default sort key is an entire line. Default ordering is lexicographic by
runes. The ordering is affected globally by the following options, one or more
of which may appear.
- -M
- Compare as months. The first three non-white space
characters of the field are folded to upper case and compared so that
precedes etc. Invalid fields compare low to
- -b
- Ignore leading white space (spaces and tabs) in field
comparisons.
- -d
- `Phone directory' order: only letters, accented letters,
digits and white space are significant in comparisons.
- -f
- Fold lower case letters onto upper case. Accented
characters are folded to their non-accented upper case form.
- -i
- Ignore characters outside the ASCII range
040-0176 in non-numeric comparisons.
- -w
- Like -i, but ignore only tabs and spaces.
- -n
- An initial numeric string, consisting of optional white
space, optional plus or minus sign, and zero or more digits with optional
decimal point, is sorted by arithmetic value.
- -g
- Numbers, like -n but with optional e-style
exponents, are sorted by value.
- -r
- Reverse the sense of comparisons.
-
-tx
- `Tab character' separating fields is x.
The notation
+pos1 -pos2 restricts 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
Mbdfginr, 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. 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 strings separated by white space. White space before a
field is part of the field, except under option
-b. A
b flag may
be attached independently to
pos1 and
pos2.
The notation
-k pos1[,
pos2] is how POSIX
sort
defines fields:
pos1 and
pos2 have the same format but different
meanings. The value of
m is origin 1 instead of origin 0 and a missing
.n in
pos2 is the end of the field.
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.
These option arguments are also understood:
- -c
- Check that the single input file is sorted according to the
ordering rules; give no output unless the file is out of sort.
- -m
- Merge; assume the input files are already sorted.
- -u
- Suppress all but one in each set of equal lines. Ignored
bytes and bytes outside keys do not participate in this comparison.
- -o
- The next argument is the name of an output file to use
instead of the standard output. This file may be the same as one of the
inputs.
-
-Tdir
- Put temporary files in dir rather than in
/var/tmp.
- Print in alphabetical order all the unique spellings
- in a list of words where capitalized words differ from
uncapitalized.
- Print the users file
- sorted by user name (the second colon-separated
field).
- Print the first instance of each month in an already sorted
file.
- Options -um with just one input file make the choice
of a unique representative from a set of equal lines predictable.
- grep -n '^' input | sort -t: +1f +0n | sed
's/[0-9]*://'
- A stable sort: input lines that compare equal will come out
in their original order.
/var/tmp/sort.<pid>.<ordinal>
/src/cmd/sort.c
uniq(1),
look(1)
Sort comments and exits with non-null status for various trouble
conditions and for disorder discovered under option
-c.
An external null character can be confused with an internally generated
end-of-field character. The result can make a sub-field not sort less than a
longer field.
Some of the options, e.g.
-i and
-M, are hopelessly
provincial.