sort(1) UNIX System V(Essential Utilities) sort(1)
NAME
sort - sort and/or merge files
SYNOPSIS
sort [-cmu] [-ooutput] [-ykmem] [-zrecsz] [-dfiMnr] [-btx]
[+pos1 [-pos2]] [files]
DESCRIPTION
The sort command 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 having 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 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
maximum 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 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.
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sort(1) UNIX System V(Essential Utilities) sort(1)
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 characters of the
field are folded to upper case and compared. 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 below).
-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 below). 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 below), the specified ordering
options override all global ordering options for that key.
The notation +pos1 -pos2 restricts a sort key to one beginning 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 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 considered to be
part of a field (although it may be included in a sort key). Each
occurrence of x is significant (for example, xx delimits an empty
field).
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sort(1) UNIX System V(Essential Utilities) sort(1)
pos1 and pos2 each have the form m.n optionally followed by one or more
of the flags bdfiMnr. A starting position specified 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 character of the m th
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 otherwise 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
Print the password file [passwd(4)] sorted by the numeric user ID (the
third colon-separated field):
sort -t: +2n -3 /etc/passwd
Sort the contents of the password file using the group ID (third field)
as the primary sort key and the user ID (second field) as the secondary
sort key:
sort -t: +3 -4 +2 -3 /etc/passwd
Print the lines of the already sorted file infile, suppressing 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):
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sort(1) UNIX System V(Essential Utilities) sort(1)
sort -um +2 -3 infile
FILES
/var/tmp/stm???
SEE ALSO
comm(1), join(1), uniq(1).
NOTES
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 ordering on equal
keys.
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