| JOIN(1) | General Commands Manual | JOIN(1) | 
join —
| join | [ -afile_number |-vfile_number]
      [-estring]
      [-jfile_number field]
      [-olist]
      [-tchar]
      [-1field]
      [-2field]
      file1 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-a must not be preceded by a space; see the
      COMPATIBILITY section.)-e
    string-o
    list-o option specifies the fields that will be
      output from each file for each line with matching join fields. Each
      element of list has the form
      ‘file_number.field’, where
      file_number is a file number and
      field is a field number. 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-v
    file_number-v 1 and
      -v 2 may be specified at the
      same time.-1
    field-2
    fieldWhen 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 used.
join utility exits 0 on success,
  and >0 if an error occurs.
join, the
  following options are available:
-a-a file_number,
      join currently requires that the latter not
      include any white space.)-j1
    field-j2
    field-j
    field-o
    list ...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 don't require modification and should not be used.
join command is expected to be IEEE
  Std 1003.2 (“POSIX.2”) compatible.
| April 28, 1995 | NetBSD 10.1 |