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SORT(1)                 FreeBSD General Commands Manual                SORT(1)

NAME
       sort - sort lines of text files

SYNOPSIS
       sort [-cmus] [-t separator] [-o output-file] [-T tempdir] [-bdfiMnr]
       [+POS1 [-POS2]] [-k POS1[,POS2]] [file...]
       sort {--help,--version}

DESCRIPTION
       This manual page documents the GNU version of sort.  sort sorts,
       merges, or compares all the lines from the given files, or the standard
       input if no files are given.  A file name of `-' means standard input.
       By default, sort writes the results to the standard output.

       sort has three modes of operation: sort (the default), merge, and check
       for sortedness.  The following options change the operation mode:

       -c     Check whether the given files are already sorted: if they are
              not all sorted, print an error message and exit with a status of
              1.

       -m     Merge the given files by sorting them as a group.  Each input
              file should already be individually sorted.  It always works to
              sort instead of merge; merging is provided because it is faster,
              in the case where it works.

       A pair of lines is compared as follows: if any key fields have been
       specified, sort compares each pair of fields, in the order specified on
       the command line, according to the associated ordering options, until a
       difference is found or no fields are left.

       If any of the global options Mbdfinr are given but no key fields are
       specified, sort compares the entire lines according to the global
       options.

       Finally, as a last resort when all keys compare equal (or if no
       ordering options were specified at all), sort compares the lines byte
       by byte in machine collating sequence.  The last resort comparison
       honors the -r global option.  The -s (stable) option disables this
       last-resort comparison so that lines in which all fields compare equal
       are left in their original relative order.  If no fields or global
       options are specified, -s has no effect.

       GNU sort has no limits on input line length or restrictions on bytes
       allowed within lines.  In addition, if the final byte of an input file
       is not a newline, GNU sort silently supplies one.

       If the environment variable TMPDIR is set, sort uses it as the
       directory in which to put temporary files instead of the default, /tmp.
       The -T tempdir option is another way to select the directory for
       temporary files; it overrides the environment variable.

       The following options affect the ordering of output lines.  They may be
       specified globally or as part of a specific key field.  If no key
       fields are specified, global options apply to comparison of entire
       lines; otherwise the global options are inherited by key fields that do
       not specify any special options of their own.

       -b     Ignore leading blanks when finding sort keys in each line.

       -d     Sort in `phone directory' order: ignore all characters except
              letters, digits and blanks when sorting.

       -f     Fold lower case characters into the equivalent upper case
              characters when sorting so that, for example, `b' is sorted the
              same way `B' is.

       -i     Ignore characters outside the ASCII range 040-0176 octal
              (inclusive) when sorting.

       -M     An initial string, consisting of any amount of white space,
              followed by three letters abbreviating a month name, is folded
              to UPPER case and compared in the order `JAN' < `FEB' < ... <
              `DEC.'  Invalid names compare low to valid names.

       -n     Compare according to arithmetic value an initial numeric string
              consisting of optional white space, an optional - sign, and zero
              or more digits, optionally followed by a decimal point and zero
              or more digits.

       -r     Reverse the result of comparison, so that lines with greater key
              values appear earlier in the output instead of later.

       Other options are:

       -o output-file
              Write output to output-file instead of to the standard output.
              If output-file is one of the input files, sort copies it to a
              temporary file before sorting and writing the output to
              output-file.

       -t separator
              Use character separator as the field separator when finding the
              sort keys in each line.  By default, fields are separated by the
              empty string between a non-whitespace character and a whitespace
              character.  That is to say, given the input line ` foo bar',
              sort breaks it into fields ` foo' and ` bar'.  The field
              separator is not considered to be part of either the field
              preceding or the field following it.

       -u     For the default case or the -m option, only output the first of
              a sequence of lines that compare equal.  For the -c option,
              check that no pair of consecutive lines compares equal.

       +POS1 [-POS2]
              Specify a field within each line to use as a sorting key.  The
              field consists of the portion of the line starting at POS1 and
              up to (but not including) POS2 (or to the end of the line if
              POS2 is not given).  The fields and character positions are
              numbered starting with 0.

       -k POS1[,POS2]
              An alternate syntax for specifying sorting keys.  The fields and
              character positions are numbered starting with 1.

       A position has the form f.c, where f is the number of the field to use
       and c is the number of the first character from the beginning of the
       field (for +pos) or from the end of the previous field (for -pos).  The
       .c part of a position may be omitted in which case it is taken to be
       the first character in the field.  If the -b option has been given, the
       .c part of a field specification is counted from the first nonblank
       character of the field (for +pos) or from the first nonblank character
       following the previous field (for -pos).

       A +pos or -pos argument may also have any of the option letters Mbdfinr
       appended to it, in which case the global ordering options are not used
       for that particular field.  The -b option may be independently attached
       to either or both of the +pos and -pos parts of a field specification,
       and if it is inherited from the global options it will be attached to
       both.  If a -n or -M option is used, thus implying a -b option, the -b
       option is taken to apply to both the +pos and the -pos parts of a key
       specification.  Keys may span multiple fields.

       In addition, when GNU sort is invoked with exactly one argument, the
       following options are recognized:

       --help Print a usage message on standard output and exit successfully.

       --version
              Print version information on standard output then exit
              successfully.

COMPATIBILITY
       Historical (BSD and System V) implementations of sort have differed in
       their interpretation of some options, particularly -b, -f, and -n.  GNU
       sort follows the POSIX behavior, which is usually (but not always!)
       like the System V behavior.  According to POSIX -n no longer implies
       -b.  For consistency, -M has been changed in the same way.  This may
       affect the meaning of character positions in field specifications in
       obscure cases.  If this bites you the fix is to add an explicit -b.

BUGS
       The different meaning of field numbers depending on whether -k is used
       is confusing.  It's all POSIX's fault!

FSF                           GNU Text Utilities                       SORT(1)

NAME | SYNOPSIS | DESCRIPTION | COMPATIBILITY | BUGS

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