join(1)     UNIX System V(Directory and File Management Utilities)      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 options below 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 with 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 includes 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 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.




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join(1)     UNIX System V(Directory and File Management Utilities)      join(1)


        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).

NOTES
      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 the join, sort, comm, uniq, and awk commands are
      wildly incongruous.

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








































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