JOIN(1)                                                   JOIN(1)



     NAME
          join - relational database operator

     SYNOPSIS
          join [ options ] file1 file2

     DESCRIPTION
          join forms, on the standard output, a join of the two
          relations specified by the lines of file1 and file2.  If
          file1 is -, the standard input is used.

          File1 and file2 must be sorted in increasing ASCII collating
          sequence on the fields on which they are to be joined,
          normally the first in each line [see sort(1)].

          There is one line in the output for each pair of lines in
          file1 and file2 that have identical join fields.  The output
          line normally consists of the common field, then the rest of
          the line from file1, then the rest of the line from file2.

          The default input field separators are blank, tab, or new-
          line.  In this case, multiple separators count as one field
          separator, and leading separators are ignored.  The default
          output field separator is a blank.

          Some of the below options use the argument n.  This argument
          should be a 1 or a 2 referring to either file1 or file2,
          respectively.  The following options are recognized:

          -an      In addition to the normal output, produce a line
                   for each unpairable line in file n, where n is 1 or
                   2.

          -e s     Replace empty output fields by string s.

          -jn m    Join on the mth field of file n.  If n is missing,
                   use the mth field in each file.  Fields are
                   numbered starting with 1.

          -o list  Each output line comprises the fields specified in
                   list, each element of which has the form n.m, where
                   n is a file number and m is a field number.  The
                   common field is not printed unless specifically
                   requested.

          -tc      Use character c as a separator (tab character).
                   Every appearance of c in a line is significant.
                   The character c is used as the field separator for
                   both input and output.

     EXAMPLE
          The following command line will join the password file and



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     JOIN(1)                                                   JOIN(1)



          the group file, matching on the numeric group ID, and
          outputting the login name, the group name and the login
          directory.  It is assumed that the files have been sorted in
          ASCII collating sequence on the group ID fields.

               join -j1 4 -j2 3 -o 1.1 2.1 1.6 -t: /etc/passwd
               /etc/group

     SEE ALSO
          awk(1), comm(1), sort(1), uniq(1).

     BUGS
          With default field separation, the collating sequence is
          that of sort -b; with -t, the sequence is that of a plain
          sort.

          The conventions of join, sort, comm, uniq and awk(1) are
          wildly incongruous.

          Filenames that are numeric may cause conflict when the -o
          option is used right before listing filenames.

     ORIGIN
          AT&T V.3































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