sort(1) sort(1)
NAME
sort - sort and/or merge files
SYNOPSIS
sort [-m] [-o output] [-bdfiMnru] [-t x] [-ykmem]
[-zrecsz] [-k keydef] . . . [file . . . ]
sort -c [-bdfiMnru] [-t x] [-k keydef] [-ykmem]
[-zrecsz] . . . [file]
DESCRIPTION
The sort command sorts lines of all the named files together
and writes the result on the standard output. The standard
input is read if - is used as a filename or no input files are
named.
Comparisons are based on one or more sort keys extracted from
each line of input. By default, there is one sort key, the
entire input line, and ordering is lexicographic by bytes in
machine collating sequence.
sort processes characters according to the locale specified in
the LC_CTYPE, LC_COLLATE, and LC_NUMERIC environment variables
[see LANG on environ(5)]. Multibyte characters are not
processed by some of the options.
The following options alter the default behavior:
-c Check that the input file is sorted according to the
ordering rules. If posix2 is set, give no output and
only vary the exit status.
-m Merge only, the input files are already sorted.
-u Unique: suppress all but one in each set of lines having
equal keys.
-o output
The argument given 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.
-ykmem
The amount of main memory used by sort has a large impact
on its performance. Sorting a small file in a large
amount of memory is a waste. If this option is omitted,
sort begins using a system default memory size, and
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continues to use more space as needed. If this option is
presented with a value (kmem), sort will start using that
number of kilobytes of memory, unless the administrative
minimum or maximum is violated, in which case the
corresponding extremum will be used. Thus, -y0 is
guaranteed to start with minimum memory. By convention,
-y (with no argument) starts with maximum memory.
-zrecsz
The size of the longest line read is recorded in the sort
phase so buffers can be allocated during the merge phase.
If the sort phase is omitted via the -c or -m options, a
popular system default size will be used. Lines longer
than the buffer size will cause sort to terminate
abnormally. Supplying the actual number of bytes in the
longest line to be merged (or some larger value) will
prevent abnormal termination.
If the sort phase is not omitted, then the maximum line size
is calculated and used as the recsz, overriding the value of
-z. Thus, the -z option is significant only when used with -c
or -m.
The following options override the default ordering rules.
-d ``Dictionary'' order: only alphanumeric and space
characters (as specified by the locale in LC_CTYPE) are
significant in comparisons. No comparison is performed
for multibyte characters.
-f Fold lowercase letters into uppercase (as specified by
the locale in LC_CTYPE). Does not apply to multibyte
characters.
-i Ignore non-printable characters (as specified by the
locale in LC_CTYPE). Multibyte characters are also
ignored.
-M Compare as months. The full abbreviation for the given
locale is used, regardless of the size of the
abbreviation. Month names are processed according to the
locale specified in the LC_TIME environment variable [see
LANG on environ(5)]. For example, in an English locale
the sorting order would be ``JAN'' < ``FEB'' < . . . <
``DEC.'' Invalid fields compare low to ``JAN.'' The -M
option implies the -b option (see below).
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sort(1) sort(1)
-n An initial numeric string, consisting of optional blanks,
an optional minus sign, and zero or more digits with an
optional decimal point, is sorted by arithmetic value.
The -n option implies the -b option (see below). Note
that the -b option is only effective when restricted sort
key specifications are in effect.
-r Reverse the sense of comparisons.
When ordering options appear before restricted sort key
specifications, the requested ordering rules are applied
globally to all sort keys. When attached to a specific sort
key (described below), the specified ordering options override
all global ordering options for that key.
The notation -k pos1,pos2 restricts a sort key to one
beginning at pos1 and ending at pos2. The characters at
position pos1 and pos2 are included in the sort key (provided
that pos2 does not precede pos1). A missing ,pos2 means the
end of the line.
The obsolescent notation +pos1 and -pos2 restricts a sort key
to one beginning at pos1 and ending just before pos2. The
characters at position pos1 and just before pos2 are included
in the sort key, provided that pos2 does not precede pos1.
So:
+m.n -o.p
is equivalent to:
if p == 0
-k m+1.n+1,o.0
if p > 0
-k m+1.n+1,o+1.p
All uses of -k pos1,pos2 below apply equally well to +pos1
-pos2 using the above mapping, including the flags usable in m
and n. See the EXAMPLES section for further clarification.
Specifying pos1 and pos2 involves the notion of a field, a
minimal sequence of characters followed by a field separator
or a newline. By default, the first blank (space or tab) of a
sequence of blanks acts as the field separator. All blanks in
a sequence of blanks are considered to be part of the next
field; for example, all blanks at the beginning of a line are
considered to be part of the first field. The treatment of
field separators can be altered using the options:
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sort(1) sort(1)
-b Ignore leading blanks when determining the starting and
ending positions of a restricted sort key. (Single-byte
blanks only.) If the -b option is specified before the
first -k argument, it will be applied to all those
arguments. Otherwise, the b flag may be attached
independently to each posn in -k pos1,pos2 argument (see
below).
-t x Use x as the field separator character; x is not
considered to be part of a field (although it may be
included in a sort key). Each occurrence of x is
significant (for example, xx delimits an empty field). x
may be a supplementary code set character.
pos1 and pos2 each have the form m.n optionally followed by
one or more of the flags bdfiMnr. A starting position
specified by -k m.n is interpreted to mean the nth character
in the mth field A missing .n means .1 indicating the first
character of the mth field. If the b flag is in effect n is
counted from the first non-blank in the mth field; -k m.1b
refers to the first non-blank character in the mth field.
A last position specified by -k . . . ,m.n is interpreted to
mean the nth character (including separators) of the mth
field. A missing .n means .0, indicating the last character
of the mth field. If the b flag is in effect n is counted
from the character after the last leading blank in the mth
field; -k . . . ,m.1b refers to the first non-blank in the mth
field.
The b flag affects only the posn that it is attached to. The
other flags (dfiMnr) can be attached to either pos1 or pos2 or
both, and always affect both specifiers.
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.
EXAMPLES
Sort the contents of infile with the second field as the sort
key:
sort -k 2,2 infile
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sort(1) sort(1)
Sort, in reverse order, the contents of infile1 and infile2,
placing the output in outfile and using the first character of
the second field as the sort key:
sort -r -o outfile -k 2.1,2.1 infile1 infile2
Sort, in reverse order, the contents of infile1 and infile2
using the first non-blank character of the second field as the
sort key:
sort -r -k 2.1b,2.1b infile1 infile2
Print the password file [passwd(4)] sorted by the numeric user
ID (the third colon-separated field):
sort -t : -k 3,3n /etc/passwd
Sort the contents of the password file using the group ID
(fourth field) as the primary sort key and the user ID (third
field) as the secondary sort key:
sort -t : -k 4,4 -k 3,3 /etc/passwd
Print the lines of the already sorted file infile, suppressing
all but the first occurrence of lines having the same third
field (the options -um with just one input file make the
choice of a unique representative from a set of equal lines
predictable):
sort -um -k 3,3 infile
FILES
/var/tmp/stm???
/usr/lib/locale/locale/LC_MESSAGES/uxcore.abi
language-specific message file [See LANG on environ
(5).]
REFERENCES
comm(1), join(1), uniq(1)
NOTICES
Comments and exits with non-zero status for various trouble
conditions (for example, when input lines are too long), and
for disorder discovered under the -c option.
When the last line of an input file is missing a newline
character, sort appends one, prints a warning message, and
continues. sort does not guarantee preservation of relative
line ordering on equal keys.
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The +pos and -pos options are becoming obsolete due to POSIX.
Application writers should avoid using them.
Use the posix2 environmental variable to get POSIX.2 behavior
that is inconsistent with existing System V behavior.
Copyright 1994 Novell, Inc. Page 6