SORT(1) INTERACTIVE UNIX System SORT(1)
NAME
sort - sort and/or merge files
SYNOPSIS
sort [-cmu] [-ooutput] [-ykmem] [-zrecsz] [-dfiMnr] [-btx]
[+pos1 [-pos2]] [files]
DESCRIPTION
sort sorts lines of all the named files together and writes
the result on the standard output. The standard input is
read if - is used as a file name or no input files are
named.
Comparisons are based on one or more sort keys extracted
from each line of input. By default, there is one sort key,
the entire input line, and ordering is lexicographic by
bytes in machine-collating sequence.
The following options alter the default behavior:
-c Check that the input file is sorted according to the
ordering rules; give no output unless the file is out
of sort.
-m Merge only, the input files are already sorted.
-u Unique: suppress all but one in each set of lines hav-
ing equal keys.
-ooutput
The argument given is the name of an output file to use
instead of the standard output. This file may be the
same as one of the inputs. There may be optional
blanks between -o and output.
-ykmem
The amount of main memory used by the sort has a large
impact on its performance. Sorting a small file in a
large amount of memory is a waste. If this option is
omitted, sort begins using a system default memory
size, and continues to use more space as needed. If
this option is presented with a value, kmem, sort will
start using that number of kilobytes of memory, unless
the administrative minimum or maximum is violated, in
which case the corresponding extremum will be used.
Thus, -y0 is guaranteed to start with minimum memory.
By convention, -y (with no argument) starts with max-
imum memory.
-zrecsz
The size of the longest line read is recorded in the
sort phase so buffers can be allocated during the merge
phase. If the sort phase is omitted via the -c or -m
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options, a popular system default size will be used.
Lines longer than the buffer size will cause sort to
terminate abnormally. Supplying the actual number of
bytes in the longest line to be merged (or some larger
value) will prevent abnormal termination.
The following options override the default ordering rules.
-d ``Dictionary'' order: only letters, digits, and blanks
(spaces and tabs) are significant in comparisons.
-f Fold lower-case letters into upper case.
-i Ignore non-printable characters.
-M Compare as months. The first three non-blank charac-
ters of the field are folded to upper case and com-
pared. For example, in English the sorting order is
"JAN" < "FEB" < ... < "DEC". Invalid fields compare
low to "JAN". The -M option implies the -b option (see
the following text).
-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. The -n option implies the -b option (see the
following text). Note that the -b option is only
effective when restricted sort key specifications are
in effect.
-r Reverse the sense of comparisons.
When ordering options appear before restricted sort key
specifications, the requested ordering rules are applied
globally to all sort keys. When attached to a specific sort
key (described in the following text), the specified order-
ing options override all global ordering options for that
key.
The notation +pos1 -pos2 restricts a sort key to one begin-
ning at pos1 and ending just before pos2. The characters at
position pos1 and just before pos2 are included in the sort
key (provided that pos2 does not precede pos1). A missing
-pos2 means the end of the line.
Specifying pos1 and pos2 involves the notion of a field, a
minimal sequence of characters followed by a field separator
or a new-line. By default, the first blank (space or tab)
of a sequence of blanks acts as the field separator. All
blanks in a sequence of blanks are considered to be part of
the next field; for example, all blanks at the beginning of
a line are considered to be part of the first field. The
treatment of field separators can be altered using the
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options:
-b Ignore leading blanks when determining the starting and
ending positions of a restricted sort key. If the -b
option is specified before the first +pos1 argument, it
will be applied to all +pos1 arguments. Otherwise, the
b flag may be attached independently to each +pos1 or
-pos2 argument (see below).
-tx Use x as the field separator character; x is not con-
sidered to be part of a field (although it may be
included in a sort key). Each occurrence of x is sig-
nificant (for example, xx delimits an empty field).
Pos1 and pos2 each have the form m.n optionally followed by
one or more of the flags bdfinr. A starting position speci-
fied by +m.n is interpreted to mean the n+1st character in
the m+1st field. A missing .n means .0, indicating the
first character of the m+1st field. If the b flag is in
effect, n is counted from the first non-blank in the m+1st
field; +m.0b refers to the first non-blank character in the
m+1st field.
A last position specified by -m.n is interpreted to mean the
nth character (including separators) after the last charac-
ter of the mth field. A missing .n means .0, indicating the
last character of the mth field. If the b flag is in
effect, n is counted from the last leading blank in the
m+1st field; -m.1b refers to the first non-blank in the
m+1st field.
When there are multiple sort keys, later keys are compared
only after all earlier keys compare equal. Lines that oth-
erwise compare equal are ordered with all bytes significant.
EXAMPLES
Sort the contents of infile with the second field as the
sort key:
sort +1 -2 infile
Sort, in reverse order, the contents of infile1 and infile2,
placing the output in outfile and using the first character
of the second field as the sort key:
sort -r -o outfile +1.0 -1.2 infile1 infile2
Sort, in reverse order, the contents of infile1 and infile2
using the first non-blank character of the second field as
the sort key:
sort -r +1.0b -1.1b infile1 infile2
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Print the password file [passwd(4)] sorted by the numeric
user ID (the third colon-separated field):
sort -t: +2n -3 /etc/passwd
Print the lines of the already sorted file infile, suppress-
ing all but the first occurrence of lines having the same
third field (the options -um with just one input file make
the choice of a unique representative from a set of equal
lines predictable):
sort -um +2 -3 infile
FILES
/usr/tmp/stm???
SEE ALSO
comm(1), join(1), uniq(1).
WARNINGS
Comments and exits with non-zero status for various trouble
conditions (for example, when input lines are too long), and
for disorder discovered under the -c option.
When the last line of an input file is missing a new-line
character, sort appends one, prints a warning message, and
continues.
sort does not guarantee preservation of relative line order-
ing on equal keys.
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