SORT(1) SORT(1)

NAME
       sort - sort lines of text files

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

DESCRIPTION
       This manual page documents  the  GNU  version  of  ssoorrtt.   ssoorrtt  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, ssoorrtt writes the results to the standard output.

       ssoorrtt 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, ssoorrtt 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,  ssoorrtt  compares  the  entire  lines  according to the global
       options.

       Finally, as a last resort when all keys compare equal (or if no  order-
       ing  options  were  specified  at all), ssoorrtt 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 ssoorrtt 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 ssoorrtt silently supplies one.

       If the environment variable TTMMPPDDIIRR is set, ssoorrtt uses it as  the  direc-
       tory 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  char-
              acters when sorting so that, for example, `b' is sorted the same
              way `B' is.

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

       -M     An initial string, consisting of any amount of white space, fol-
              lowed 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, ssoorrtt 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',
              ssoorrtt breaks it into fields ` foo' and ` bar'.  The field separa-
              tor 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 num-
              bered 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 ssoorrtt 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  success-
              fully.

CCOOMMPPAATTIIBBIILLIITTYY
       Historical  (BSD and System V) implementations of ssoorrtt 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)