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JOIN(1)                 FreeBSD General Commands Manual                JOIN(1)

     join - relational database operator

     join [-a file_number | -v file_number] [-e string] [-o list] [-t char]
          [-1 field] [-2 field] file1 file2

     The join utility performs an ``equality join'' on the specified files and
     writes the result to the standard output.  The ``join field'' is the
     field in each file by which the files are compared.  The first field in
     each line is used by default.  There is one line in the output for each
     pair of lines in file1 and file2 which have identical join fields.  Each
     output line consists of the join field, the remaining fields from file1
     and then the remaining fields from file2.

     The default field separators are tab and space characters.  In this case,
     multiple tabs and spaces count as a single field separator, and leading
     tabs and spaces are ignored.  The default output field separator is a
     single space character.

     Many of the options use file and field numbers.  Both file numbers and
     field numbers are 1 based, i.e., the first file on the command line is
     file number 1 and the first field is field number 1.  The following
     options are available:

     -a file_number
             In addition to the default output, produce a line for each
             unpairable line in file file_number.

     -e string
             Replace empty output fields with string.

     -o list
             The -o option specifies the fields that will be output from each
             file for each line with matching join fields.  Each element of
             list has either the form file_number.field, where file_number is
             a file number and field is a field number, or the form `0'
             (zero), representing the join field.  The elements of list must
             be either comma (`,') or whitespace separated.  (The latter
             requires quoting to protect it from the shell, or, a simpler
             approach is to use multiple -o options.)

     -t char
             Use character char as a field delimiter for both input and
             output.  Every occurrence of char in a line is significant.

     -v file_number
             Do not display the default output, but display a line for each
             unpairable line in file file_number.  The options -v 1 and -v 2
             may be specified at the same time.

     -1 field
             Join on the field'th field of file1.

     -2 field
             Join on the field'th field of file2.

     When the default field delimiter characters are used, the files to be
     joined should be ordered in the collating sequence of sort(1), using the
     -b option, on the fields on which they are to be joined, otherwise join
     may not report all field matches.  When the field delimiter characters
     are specified by the -t option, the collating sequence should be the same
     as sort(1) without the -b option.

     If one of the arguments file1 or file2 is `-', the standard input is

     The join utility exits 0 on success, and >0 if an error occurs.

     For compatibility with historic versions of join, the following options
     are available:

     -a      In addition to the default output, produce a line for each
             unpairable line in both file1 and file2.

     -j1 field
             Join on the field'th field of file1.

     -j2 field
             Join on the field'th field of file2.

     -j field
             Join on the field'th field of both file1 and file2.

     -o list ...
             Historical implementations of join permitted multiple arguments
             to the -o option.  These arguments were of the form
             file_number.field_number as described for the current -o option.
             This has obvious difficulties in the presence of files named 1.2.

     These options are available only so historic shell scripts do not require
     modification and should not be used.

     awk(1), comm(1), paste(1), sort(1), uniq(1)

     The join command conforms to IEEE Std 1003.1-2001 (``POSIX.1'').

FreeBSD 11.0-PRERELEASE          July 5, 2004          FreeBSD 11.0-PRERELEASE


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