SORT(I)                      5/13/75                      SORT(I)


     sort, usort - sort or merge files


     sort [ -abdnrtx ] [ +pos  [ -pos ] ] . . .  [ -mo ] [ name ]

     . . .

     usort [ -umo ] [ name ] . . .


     Sort sorts all the  named  files  together  and  writes  the

     result  on  the  standard  output.   The  name `-' means the

     standard input.  The standard input is also used if no input

     file names are given.  Thus sort may be used as a filter.

     The default sort key is an entire line.  Default ordering is

     lexicographic  in  ASCII  collating  sequence,  except  that

     lower-case  letters  are  considered   the   same   as   the

     corresponding   upper-case  letters.   Non-ASCII  bytes  are

     ignored.  The ordering is affected by the flags abdnrt,  one

     or more of which may appear:

     a    Do not map lower case letters.

     b    Leading blanks (spaces and tabs) are  not  included  in


     d    `Dictionary' order: only letters, digits and blanks are

         significant in ASCII comparisons.

     n    An initial numeric string, consisting of optional minus

         sign,  digits  and optionally included decimal point, is

         sorted by arithmetic value.

     r    Reverse the sense of comparisons.

     tx   Tab character between fields is x.

     Selected parts of the line, specified by +pos and -pos,  may

     be  used  as  sort  keys.   Pos  has  the  form m.n, where m

     specifies a number of fields to skip,  and  n  a  number  of

     characters  to  skip further into the next field.  A missing

     .n is taken to be 0.  +pos denotes the beginning of the key;

     -pos  denotes  the first position after the key (end of line

     by default).  The ordering rule  may  be  overridden  for  a

     particular  key  by appending one or more of the flags abdnr

     to +pos.

     When no tab character has been specified, a  field  consists

     of  nonblanks  and any preceding blanks.  Under the -b flag,

     leading blanks are  excluded  from  a  field.   When  a  tab

     character  has  been  specified,  a field is a string ending

     with a tab character.

     When keys are specified, later keys are compared  only  when

     all  earlier  ones  compare equal.  Lines that compare equal

     are ordered with all bytes significant.

     These flag arguments are also understood:

     -m   Merge only, the input files are already sorted.

     -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, except under the  merge  flag


     Usort is  a  somewhat  specialized  version  of  sort  which

     accepts no collating sequence options: order is always plain

     ASCII.  It also strips out the second and  following  copies

     of  duplicated  lines.   A  u  flag prevents this stripping.

     Usort also understands the m and o options in the  same  way

     as sort.