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SORT(1)                     General Commands Manual                    SORT(1)

     sort - sort or merge text files

     sort [-bdfHilmnrSsu] [-k kstart[,kend]] [-o output] [-R char] [-T dir]
          [-t char] [file ...]
     sort -C|-c [-bdfilnru] [-k kstart[,kend] [-t char]] [-R char] [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 following options are available:

     -C          Identical to -c without the error messages in the case of
                 unsorted input.

     -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.  See also -u.

     -H          Ignored for compatibility with earlier versions of sort.

     -m          Merge only; the input files are assumed to be pre-sorted.

     -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.

     -S          Don't use stable sort.  Default is to use stable sort.

     -s          Use stable sort, keeps records with equal keys in their
                 original order.  This is the default.  Provided for
                 compatibility with other sort implementations only.

     -T dir      Use dir as the directory for temporary files.  The default is
                 the value specified in the environment variable TMPDIR or
                 /tmp if TMPDIR is not defined.

     -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, which should be given before any -k options,
     override the default ordering rules.  When ordering options appear
     independent of, and before, 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.

     -l          Sort by the string length of the field, not by the field

     -n          An initial numeric string, consisting of optional blank
                 space, optional plus or 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.

     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.

     -k kstart[,kend]
                 Designates the starting position, kstart, and optional ending
                 position, kend, of a key field.  The -k option replaces the
                 obsolescent options +pos1 and -pos2.

     -R char     char is used as the record separator character.  This should
                 be used with discretion; -R <alphanumeric> usually produces
                 undesirable results.  If char is not a single character, then
                 it specifies the value of the desired record separator as an
                 integer specified in any of the normal NNN, 0ooo, or 0xXXX
                 ways, or as an octal value preceded by \.  Caution: do not
                 attempt to specify Ctl-A as "-R 1" which will not do what was
                 intended at all!  The default record separator is newline.

     -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 (see below).  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 blank-space 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.

     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 minimal sequence of characters followed by a
     field separator or a newline character.  By default, the first blank
     space of a sequence of blank spaces acts as the field separator.  All
     blank spaces in a sequence of blank spaces are considered as part of the
     next field; for example, all blank spaces at the beginning of a line are
     considered to be part of the first field.

     Fields are specified by the -k kstart[,kend] argument.  A missing kend
     argument defaults to the end of a line.

     The arguments kstart and kend have the form m.n and can be followed by
     one or more of the letters b, d, f, i, l, n, and r, which correspond to
     the options discussed above.  A kstart position specified by m.n (m, n >
     0) is interpreted as the nth character in the mth field.  A missing .n in
     kstart 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.

     A kend 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+1.0.  The obsolescent +pos1 -pos2 option is still supported,
     except for -w.0b, which has no -k equivalent.

     sort compares records by comparing the key fields selected by -k
     arguments, from first given to last, until discovering a difference.  If
     there are no -k arguments, the whole record is treated as a single key.
     After exhausting the -k arguments, if no difference has been found, then
     the result depends upon the -u and -S option settings.  With -u the
     records are considered identical, and one is suppressed.  Otherwise with
     -s set (default) the records are left in their original order, or with -S
     (posix mode) the whole record is considered as a tie breaker.

     If the following environment variable exists, it is used by sort.

     TMPDIR           sort uses the contents of the TMPDIR environment
                      variable as the path in which to store temporary files.

     /tmp/sort.*        Default temporary files.
     outputNUMBER       Temporary file which is used for output if output
                        already exists.  Once sorting is finished, this file
                        replaces output (via link(2) and unlink(2)).

     Sort exits with one of the following values:
     0     Normal behavior.
     1     On disorder (or non-uniqueness) with the -c (or -C) option.
     2     An error occurred.

     comm(1), join(1), uniq(1), qsort(3), radixsort(3)

     A sort command appeared in Version 1 AT&T UNIX.  This sort implementation
     appeared in 4.4BSD and is used since NetBSD 1.6.

     Posix requires the locale's thousands separator be ignored in numbers.
     It may be faster to sort very large files in pieces and then explicitly
     merge them.

     This 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.

     Input files should be text files.  If file doesn't end with record
     separator (which is typically newline), the sort utility silently
     supplies one.

     The current sort 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 kend argument of
     the -k option should be used whenever possible.  Similarly, sort -k1f is
     equivalent to sort -f and may take twice as long.

NetBSD 10.99                   September 1, 2019                  NetBSD 10.99