SORT(1)                                                   SORT(1)

          sort - sort or merge files

          sort [ -m_u_b_d_f_i_n_r_t_x ] [ +pos1  [ -pos2 ] ] ...  [ -o name ] [
          -T directory ] [ name ] ...

          Sort sorts lines of all the named files together and writes
          the result on the standard output.  The name `-' means the
          standard input.  If no input files are named, the standard
          input is sorted.

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

          b    Ignore leading blanks (spaces and tabs) in field com-

          d    `Dictionary' order: only letters, digits and blanks are
               significant in comparisons.

          f    Fold upper case letters onto lower case.

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

          n    An initial numeric string, consisting of optional
               blanks, optional minus sign, and zero or more digits
               with optional decimal point, is sorted by arithmetic
               value.  Option n implies option b.

          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 bdfinr, 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.  If
          the b option is in effect n is counted from the first non-
          blank in the field; b is attached independently to pos2. 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 nonempty nonblank strings separated

     SORT(1)                                                   SORT(1)

          by blanks.

          When there are multiple sort keys, later keys are compared
          only after all earlier keys compare equal.  Lines that oth-
          erwise compare equal are ordered with all bytes significant.

          These option arguments are also understood:

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

          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.

          T    The next argument is the name of a directory in which
               temporary files should be made.

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

          Examples. Print in alphabetical order all the unique spel-
          lings in a list of words.  Capitalized words differ from

                  sort -u +0f +0 list

          Print the password file (passwd(5)) sorted by user id number
          (the 3rd colon-separated field).

                  sort -t: +2n /etc/passwd

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

                  sort -um +0 -1 dates

          /usr/tmp/stm*, /tmp/*: first and second tries for temporary

          uniq(1), comm(1), rev(1), join(1)

          Comments and exits with nonzero status for various trouble

     SORT(1)                                                   SORT(1)

          conditions and for disorder discovered under option -c.

          Very long lines are silently truncated.