SORT(1) SORT(1)
NAME
sort - sort and/or merge files
SYNOPSIS
sort [ -cmusMbdfinrtx ] [ -o output ] [ option ... ] [ file
... ]
DESCRIPTION
Sort sorts lines of all the files together and writes the
result on the standard output. The name - means the stan-
dard input. If no input files are named, the standard input
is sorted.
The default sort key is an entire line. Default ordering is
lexicographic by bytes in machine collating sequence. The
ordering is affected globally by the following options, one
or more of which may appear.
-b Ignore leading white space (spaces and tabs) in field
comparisons.
-d `Phone directory' order: only letters, digits and white
space are significant in string comparisons.
-f Fold lower case letters onto upper case.
-i Ignore characters outside the ASCII range 040-0176 in
string comparisons.
-n An initial numeric string, consisting of optional white
space, optional sign, and a nonempty string of digits
with optional decimal point, is sorted by value.
-g Numeric, like -n, with e-style exponents allowed.
-M Compare as month names. The first three characters
after optional white space are folded to lower case and
compared. Invalid fields compare low to `jan'.
-r Reverse the sense of comparisons.
-tx `Tab character' separating fields is x.
-k pos1,pos2
Restrict the sort key to a string beginning at pos1 and
ending at pos2. Pos1 and pos2 each have the form m.n,
optionally followed by one or more of the flags
Mbdfginr; m counts fields from the beginning of the
line and n counts characters from the beginning of the
field. If any flags are present they override all the
SORT(1) SORT(1)
global ordering options for this key. If .n is missing
from pos1, it is taken to be 1; if missing from pos2,
it is taken to be the end of the field. If pos2 is
missing, it is taken to be end of line.
Under option -tx fields are strings separated by x; other-
wise 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.
When there are multiple sort keys, later keys are compared
only after all earlier keys compare equal. Except under
option -s, lines with all keys equal are ordered with all
bytes significant.
Single-letter options may be combined into a single string,
such as -cnrt:. The option combination -di and the combina-
tion of -n with any of -diM are improper. Posix argument
conventions are supported.
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; the input files are already sorted.
-u Unique. Keep only the first of two lines that compare
equal on all keys. Implies -s.
-s Stable sort. When all keys compare equal, preserve
input order. Unaffected by -r.
-o output
Place output in a designated file instead of on the
standard output. This file may be the same as one of
the inputs. The option may appear among the file argu-
ments, except after --.
-T tempdir
Put temporary files in tempdir rather than in (the
default) /usr/tmp.
-ymemory
Suggests using the specified number of bytes of inter-
nal store to tune performance; an unspecified memory
size is taken to be huge.
+pos1 -pos2
Classical alternative to -k, with counting from 0
SORT(1) SORT(1)
instead of 1, and pos2 designating next-after-last
instead of last character of the key. A missing char-
acter count in pos2 means 0, which in turn excludes any
-t tab character from the end of the key. Thus +1 -1.3
means the same as -k 2,2.3 and +1r -3 means the same as
-k 2r,3.
EXAMPLES
`sort -u -k1f -k1 list'
Print in alphabetical order all the unique spellings in
a list of words where capitalized words differ from
uncapitalized.
`sort -t: -k3n /etc/passwd'
Print the password file (passwd(5)) sorted by userid
(the third colon-separated field).
`sort -umM dates'
Print the first instance of each month in an already
sorted file.
FILES
SEE ALSO
comm(1), join(1), uniq(1), look(1)
DIAGNOSTICS
Sort comments and exits with non-zero status for various
trouble conditions and for disorder discovered under option
-c.
BUGS
The never-documented default pos1=0 for cases such as sort
-1 has been abolished.
Trouble (e.g. crash or file-system overflow) encountered
while overwriting an input with -o is irrecoverable.