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SORT(1) System General Commands Manual SORT(1)
NAME
sort - sort or merge text files
SYNOPSIS
sort [-bcdfHimnprsuz] [-t char] [-R char] [-k field1[,field2]] ...
[-T dir] [-o output] [file] ...
DESCRIPTION
The sort utility sorts text files by lines. Comparisons are based on one
or more sort keys extracted from each line of input, and are performed
lexicographically. By default, if keys are not given, sort regards each
input line as a single field.
The options are as follows:
-c, --check
Check that the single input file is sorted. If the file is not
sorted, sort produces the appropriate error messages and exits
with code 1; otherwise, sort returns 0. sort -c produces no out-
put, except the error messages on stderr.
-m, --merge
Merge only; the input files are assumed to be pre-sorted.
-o output, --output output
The argument given is the name of an output file to be used
instead of the standard output. This file can be the same as one
of the input files.
-T dir, --temporary-directory dir
Use dir as the directory for temporary files. The default is the
contents of the environment variable TMPDIR or /var/tmp if TMPDIR
does not exist.
-u, --unique
Unique: suppress all but one in each set of lines having equal
keys. If used with the -c option, check that there are no lines
with duplicate keys.
The following options override the default ordering rules. When ordering
options appear independent of key field specifications, the requested
field ordering rules are applied globally to all sort keys. When
attached to a specific key (see -k), the ordering options override all
global ordering options for that key.
-d, --dictionary-order
Only blank space and alphanumeric characters are used in making
comparisons.
-f, --ignore-case
Considers all lowercase characters that have uppercase equiva-
lents to be the same for purposes of comparison.
-i, -ignore-nonprinting
Ignore all non-printable characters.
-n, --numeric-sort
An initial numeric string, consisting of optional blank space,
optional minus sign, and zero or more digits (including decimal
point) is sorted by arithmetic value. (The -n option no longer
implies the -b option.)
-p, --package-separators
Add the characters '-' and '.' as field separators. This is an
option added to help with the correct sorting of software package
names in conjuntion with the '-k' option.
-r, --reverse-sort
Reverse the sense of comparisons.
-s, --stable-sort
Enable stable sort. Use additional resources.
-H, --merge-sort
Use a merge sort instead of a radix sort. This option should be
used for files larger than 60Mb.
The treatment of field separators can be altered using these options:
-b, --ignore-leading-blanks
Ignores leading blank space when determining the start and end of
a restricted sort key. A -b option specified before the first -k
option applies globally to all -k options. Otherwise, the -b
option can be attached independently to each field argument of
the -k option (see below). Note that the -b option has no effect
unless key fields are specified.
-t char, --field-separator char
char is used as the field separator character. The initial char
is not considered to be part of a field when determining key off-
sets. Each occurrence of char is significant (for example,
``charchar'' delimits an empty field). If -t is not specified,
the default field separator is a sequence of blank-space charac-
ters, and consecutive blank spaces do not delimit an empty field;
further, the initial blank space is considered part of a field
when determining key offsets.
-R char, --record-separator char
char is used as the record separator character. This should be
used with discretion; -R usually produces undesir-
able results. The default record separator is newline.
-k field1[,field2], --key [field1[,field2]
Designates the starting position, field1, and optional ending
position, field2, of a key field. The -k option replaces the
obsolescent options +pos1 and -pos2.
-z, --nul-record-separator
Use the NUL character as the record separator.
The following operands are available:
file The pathname of a file to be sorted, merged, or checked. If no
file operands are specified, or if a file operand is -, the stan-
dard input is used.
A field is defined as a maximal sequence of characters other than the
field separator and record separator (newline by default). Initial blank
spaces are included in the field unless -b has been specified; the first
blank space of a sequence of blank spaces acts as the field separator and
is included in the field (unless -t is specified). For example, by
default all blank spaces at the beginning of a line are considered to be
part of the first field.
Fields are specified by the -k field1[,field2] argument. A missing
field2 argument defaults to the end of a line.
The arguments field1 and field2 have the form m.n (m,n > 0) and can be
followed by one or more of the letters b, d, f, i, n, and r, which corre-
spond to the options discussed above. A field1 position specified by m.n
is interpreted as the nth character from the beginning of the mth field.
A missing .n in field1 means `.1', indicating the first character of the
mth field; if the -b option is in effect, n is counted from the first
non-blank character in the mth field; m.1b refers to the first non-blank
character in the mth field. 1.n refers to the nth character from the
beginning of the line; if n is greater than the length of the line, the
field is taken to be empty.
A field2 position specified by m.n is interpreted as the nth character
(including separators) of the mth field. A missing .n indicates the last
character of the mth field; m = 0 designates the end of a line. Thus the
option -k v.x,w.y is synonymous with the obsolescent option +v-1.x-1
-w-1.y; when y is omitted, -k v.x,w is synonymous with +v-1.x-1 -w.0.
The obsolescent +pos1 -pos2 option is still supported, except for -w.0b,
which has no -k equivalent.
The sort utility shall exit with one of the following values:
0 Normal behavior.
1 On disorder (or non-uniqueness) with the -c option.
2 An error occurred.
ENVIRONMENT
TMPDIR Path in which to store temporary files. Note that TMPDIR may
be overridden by the -T option.
FILES
/var/tmp/sort.* default temporary directories
~ output#PID temporary name for output if output
already exists
SEE ALSO
comm(1), join(1), uniq(1), radixsort(3), sradixsort(3)
STANDARDS
This utility is meets the POSIX 1003.1 specification. The options
-HpRsTz are enhancements that may not be portable to all other systems.
HISTORY
A sort command appeared in Version 3 AT&T UNIX.
NOTES
sort has no limits on input line length (other than imposed by available
memory) or any restrictions on bytes allowed within lines.
To protect data sort -o calls link(2) and unlink(2), and thus fails on
protected directories.
The current sort command uses lexicographic radix sorting, which requires
that sort keys be kept in memory (as opposed to previous versions which
used quick and merge sorts and did not). Thus performance depends highly
on efficient choice of sort keys, and the -b option and the field2 argu-
ment of the -k option should be used whenever possible. Similarly, sort
-k1f is equivalent to sort -f and may take twice as long.
BUGS
To sort files larger than 60Mb, use sort -H; files larger than 704Mb must
be sorted in smaller pieces, then merged.
Interix June 5, 2009 Interix