sort - sort or merge text files
sort [-cmubdfinrH] [-t char] [-R char] [-k field1[,field2]]
... [-T dir]
[-o output] [file] ...
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 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 output,
except the error messages on stderr.
-m Merge only; the input files are assumed to be presorted.
-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 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 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.
-H 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 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
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 blankspace 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.
-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.
-k 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.
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.
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.
TMPDIR Path in which to store temporary files. Note
that TMPDIR may
be overridden by the -T option.
/var/tmp/sort.* default temporary directories
output#PID temporary name for output
if output already
exists
comm(1), join(1), uniq(1), radixsort(3)
A sort command appeared in Version 3 AT&T UNIX.
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 argument
of the -k option should be used whenever possible.
Similarly, sort
-k1f is equivalent to sort -f and may take twice as long.
To sort files larger than 60Mb, use sort -H; files larger
than 704Mb must
be sorted in smaller pieces, then merged.
OpenBSD 3.6 June 6, 1993
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