term% cat index.txt SORT(1) General Commands Manual SORT(1)
NAME
sort - sort and/or merge files
SYNOPSIS
sort [ -cmuMbdfinrtx ] [ +pos1 [ -pos2 ] ] ... [ -o output ] [ -ymemory
] [ -zrecsize ] [ names ]
DESCRIPTION
Sort sorts lines of all the named files together and writes the result
on the standard output. The name - means the standard input. If no
input files are named, the standard input is sorted.
The default sort key is an entire line. Default ordering is lexico‐
graphic by bytes in machine collating sequence. The ordering is af‐
fected globally by the following options, one or more of which may ap‐
pear.
M Compare as months. The first three non-blank characters of the
field are folded to lower case and compared so that ‘jan' < ‘feb'
< ... < ‘dec'. Invalid fields compare low to ‘jan'.
b Ignore leading blanks (spaces and tabs) in field comparisons.
d ‘Dictionary' order: only letters, digits and blanks are signifi‐
cant in comparisons.
f Fold upper case letters onto lower case.
i Ignore characters outside the ASCII range 040-0176 in non-numeric
comparisons.
n An initial numeric string, consisting of optional blanks, optional
minus sign, and zero or more digits with optional decimal point,
is sorted by arithmetic value. Option n implies option b.
r Reverse the sense of comparisons.
tx ‘Tab character' separating fields is x.
The notation +pos1 -pos2 restricts a sort key to a field beginning at
pos1 and ending just before pos2. Pos1 and pos2 each have the form
m.n, optionally followed by one or more of the flags Mbdfinr, where m
tells a number of fields to skip from the beginning of the line and n
tells a number of characters to skip further. If any flags are present
they override all the global ordering options for this key. If the b
option is in effect n is counted from the first non-blank in the field;
b is attached independently to pos2. A missing .n means .0; a missing
-pos2 means the end of the line. Under the -tx option, fields are
strings separated by x; otherwise fields are non-empty non-blank
strings separated by blanks. The blanks separating fields are consid‐
ered the first characters in the field.
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.
These option arguments are also understood:
c Check that the single input file is sorted according to the order‐
ing rules; give no output unless the file is out of sort.
m Merge only, the input files are already sorted.
u Suppress all but one in each set of equal lines. Ignored bytes
and bytes outside keys do not participate in this comparison.
o The next argument is the name of an output file to use instead of
the standard output. This file may be the same as one of the in‐
puts.
ymemory
Suggests the use of the specified number of bytes of internal
store in hopes of tuning performance; 0 is appropriate for very
small files, a missing number for huge ones.
zrecsize
provide for abnormally large records; useful only with -c and -m
EXAMPLES
sort -u +0f +0 list
Print in alphabetical order all the unique spellings in a list
of words where capitalized words differ from uncapitalized.
sort -t: +2n /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. Options -um with just one input file make the choice of a
unique representative from a set of equal lines predictable.
FILES
/usr/tmp/stm???
SEE ALSO
comm(1), join(1), uniq(1).
DIAGNOSTICS
Comments and exits with non-zero status for various trouble conditions
and for disorder discovered under option -c.
SORT(1)