NAME

       sort - sort and/or merge files

SYNOPSIS

       sort [ -cmuMbdfinrwtx ] [ +pos1 [ -pos2 ] ...  ] ...  [ -k pos1 [ ,pos2 ] ] ...
            ' [ -o output ] [ -T dir ...  ] [ option ...  ] [ file ...  ]

DESCRIPTION

       Sort  sorts  lines of all the files together and writes the result on the standard output.
       If no input files are named, the standard input is sorted.

       The default sort key is an entire line.  Default ordering is lexicographic by runes.   The
       ordering is affected globally by the following options, one or more of which may appear.

       -M     Compare  as  months.   The  first three non-white space characters of the field are
              folded to upper case and compared so that precedes etc.  Invalid fields compare low
              to

       -b     Ignore leading white space (spaces and tabs) in field comparisons.

       -d     `Phone directory' order: only letters, accented letters, digits and white space are
              significant in comparisons.

       -f     Fold lower case letters onto upper case.  Accented characters are folded  to  their
              non-accented upper case form.

       -i     Ignore characters outside the ASCII range 040-0176 in non-numeric comparisons.

       -w     Like -i, but ignore only tabs and spaces.

       -n     An  initial  numeric  string,  consisting of optional white space, optional plus or
              minus sign, and zero or more digits with  optional  decimal  point,  is  sorted  by
              arithmetic value.

       -g     Numbers, like -n but with optional e-style exponents, are sorted by value.

       -r     Reverse the sense of comparisons.

       -tx    `Tab character' separating fields is x.

       The notation +pos1 -pos2 restricts a sort key to a field beginning at pos1 and ending just
       before pos2.  Pos1 and pos2 each have the form m.n, optionally followed by one or more  of
       the  flags  Mbdfginr,  where  m tells a number of fields to skip from the beginning of the
       line and n tells a number of characters to skip further.  If any flags  are  present  they
       override  all  the global ordering options for this key.  A missing .n means .0; a missing
       -pos2 means the end of the line.  Under the -tx option, fields are strings separated by x;
       otherwise  fields  are  non-empty  strings separated by white space.  White space before a
       field is part  of  the  field,  except  under  option  -b.   A  b  flag  may  be  attached
       independently to pos1 and pos2.

       The  notation -k pos1[,pos2] is how POSIX sort defines fields: pos1 and pos2 have the same
       format but different meanings.  The value of m is origin 1  instead  of  origin  0  and  a
       missing .n in pos2 is the end of the 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.

       These option arguments are also understood:

       -c         Check that the single input file is sorted according  to  the  ordering  rules;
                  give no output unless the file is out of sort.

       -m         Merge; assume the input files are already sorted.

       -u         Suppress  all  but  one  in  each  set of equal lines.  Ignored bytes and bytes
                  outside keys do not participate in this comparison.

       -o         The next argument 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.

       -Tdir      Put temporary files in dir rather than in /var/tmp.

EXAMPLES

       Print in alphabetical order all the unique spellings
              in a list of words where capitalized words differ from uncapitalized.

       Print the users file
              sorted by user name (the second colon-separated field).

       Print the first instance of each month in an already sorted file.
              Options  -um  with  just  one input file make the choice of a unique representative
              from a set of equal lines predictable.

       grep -n '^' input | sort -t: +1f +0n | sed 's/[0-9]*://'
              A stable sort: input lines that compare equal  will  come  out  in  their  original
              order.

FILES

       /var/tmp/sort.<pid>.<ordinal>

SOURCE

       /src/cmd/sort.c

SEE ALSO

       uniq(1), look(1)

DIAGNOSTICS

       Sort  comments  and  exits  with  non-null  status  for various trouble conditions and for
       disorder discovered under option -c.

BUGS

       An external null character can be  confused  with  an  internally  generated  end-of-field
       character.  The result can make a sub-field not sort less than a longer field.

       Some of the options, e.g.  -i and -M, are hopelessly provincial.

                                                                                     SORT(1plan9)