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)