SORT(1) OpenBSD Reference Manual SORT(1)NAMEsort - sort, merge, or sequence check text files
SYNOPSISsort [-bCcdfHimnrsuz] [-k field1[,field2]] [-o output] [-R char] [-T dir]
[-t char] [file ...]
DESCRIPTION
The sort utility sorts text files by lines, operating in one of three
modes: sort, merge, or check. In sort mode, the specified files are
combined and sorted by line. Merge mode is the same as sort mode except
that the input files are assumed to be pre-sorted. In check mode, a
single input file is checked to ensure that it is correctly sorted.
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 that the single input file is sorted. If it is, exit 0; if
it's not, exit 1. In either case, produce no output.
-c Like -C, but additionally write a message to stderr if the input
file is not sorted.
-m Merge only; the input files are assumed to be pre-sorted. This
option is overridden by the -C or -c options, if they are also
present.
-o 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 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: suppress all but one in each set of lines having equal
keys. If used with the -C or -c options, also check that there
are no lines with duplicate keys.
The following options override the default ordering rules globally:
-H Use a merge sort instead of a radix sort. This option should be
used for files larger than 60Mb.
-s Enable stable sort. Uses additional resources (see
sradixsort(3)).
The following options override the default ordering rules. If ordering
options appear before the first -k option, they apply globally to all
sort keys. When attached to a specific key (see -k), the ordering
options override all global ordering options for that key. Note that the
ordering options intended to apply globally should not appear after -k or
results may be unexpected.
-d Only blank space and alphanumeric characters are used in making
comparisons.
-f Considers all lowercase characters that have uppercase
equivalents to be the same for purposes of comparison.
-i Ignore all non-printable characters.
-n 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.)
-r Reverse the sense of comparisons.
The treatment of field separators can be altered using these options:
-b 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 -b should not appear after
-k, and that it has no effect unless key fields are specified.
-R char
char is used as the record separator character. This should be
used with discretion; -R <alphanumeric> usually produces
undesirable results. The default record separator is newline.
-t char
char is used as the field separator character. The initial char
is not considered to be part of a field when determining key
offsets. 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
characters, 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.
-z Uses the nul character as the record separator.
Sort keys are specified with:
-k field1[,field2]
Designates the starting position, field1, and optional ending
position, field2, of a key field. The -k option may be specified
multiple times, in which case subsequent keys are compared after
earlier keys compare equal. The -k option replaces the
obsolescent options +pos1 and -pos2.
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
standard 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
correspond 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.
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
EXIT STATUS
The sort utility exits with one of the following values:
0 Normal behavior.
1 The input file is not sorted and -C or -c was given, or
there are duplicate keys and -Cu or -cu was given.
2 An error occurred.
SEE ALSOcomm(1), join(1), uniq(1), radixsort(3)STANDARDS
The sort utility is compliant with the IEEE Std 1003.1-2008 (``POSIX'')
specification.
The flags [-HRsTz] are extensions to that specification.
HISTORY
A sort command appeared in Version 3 AT&T UNIX.
NOTESsort 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
argument 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.
OpenBSD 4.9 September 3, 2010 OpenBSD 4.9
