.\" Copyright (c) 1990, 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" This code is derived from software contributed to Berkeley by .\" the Institute of Electrical and Electronics Engineers, Inc. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed by the University of .\" California, Berkeley and its contributors. .\" 4. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#)join.1 8.3 (Berkeley) 4/28/95 .\" $FreeBSD: src/usr.bin/join/join.1,v 1.20 2005/02/13 22:25:23 ru Exp $ .\" .Dd July 5, 2004 .Dt JOIN 1 .Os .Sh NAME .Nm join .Nd relational database operator .Sh SYNOPSIS .Nm .Oo .Fl a Ar file_number | Fl v Ar file_number .Oc .Op Fl e Ar string .Op Fl o Ar list .Bk -words .Ek .Op Fl t Ar char .Op Fl \&1 Ar field .Op Fl \&2 Ar field .Ar file1 .Ar file2 .Sh DESCRIPTION The .Nm utility performs an .Dq equality join on the specified files and writes the result to the standard output. The .Dq 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 .Ar file1 and .Ar file2 which have identical join fields. Each output line consists of the join field, the remaining fields from .Ar file1 and then the remaining fields from .Ar file2 . .Pp 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. .Pp 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: .Bl -tag -width indent .It Fl a Ar file_number In addition to the default output, produce a line for each unpairable line in file .Ar file_number . .It Fl e Ar string Replace empty output fields with .Ar string . .It Fl o Ar list The .Fl o option specifies the fields that will be output from each file for each line with matching join fields. Each element of .Ar list has the either the form .Ql file_number.field , where .Ar file_number is a file number and .Ar field is a field number, or the form .Ql 0 .Pq zero , representing the join field. The elements of list must be either comma .Pq Ql \&, or whitespace separated. (The latter requires quoting to protect it from the shell, or, a simpler approach is to use multiple .Fl o options.) .It Fl t Ar char Use character .Ar char as a field delimiter for both input and output. Every occurrence of .Ar char in a line is significant. .It Fl v Ar file_number Do not display the default output, but display a line for each unpairable line in file .Ar file_number . The options .Fl v Ar 1 and .Fl v Ar 2 may be specified at the same time. .It Fl 1 Ar field Join on the .Ar field Ns 'th field of file 1. .It Fl 2 Ar field Join on the .Ar field Ns 'th field of file 2. .El .Pp When the default field delimiter characters are used, the files to be joined should be ordered in the collating sequence of .Xr sort 1 , using the .Fl b option, on the fields on which they are to be joined, otherwise .Nm may not report all field matches. When the field delimiter characters are specified by the .Fl t option, the collating sequence should be the same as .Xr sort 1 without the .Fl b option. .Pp If one of the arguments .Ar file1 or .Ar file2 is .Dq - , the standard input is used. .Sh EXIT STATUS .Ex -std .Sh COMPATIBILITY For compatibility with historic versions of .Nm , the following options are available: .Bl -tag -width indent .It Fl a In addition to the default output, produce a line for each unpairable line in both file 1 and file 2. .It Fl j1 Ar field Join on the .Ar field Ns 'th field of file 1. .It Fl j2 Ar field Join on the .Ar field Ns 'th field of file 2. .It Fl j Ar field Join on the .Ar field Ns 'th field of both file 1 and file 2. .It Fl o Ar list ... Historical implementations of .Nm permitted multiple arguments to the .Fl o option. These arguments were of the form .Ql file_number.field_number as described for the current .Fl o option. This has obvious difficulties in the presence of files named .Ql 1.2 . .El .Pp These options are available only so historic shell scripts do not require modification. They should not be used in new code. .Sh LEGACY DESCRIPTION The .Fl e option causes a specified string to be substituted into empty fields, even if they are in the middle of a line. In legacy mode, the substitution only takes place at the end of a line. .Pp Only documented options are allowed. In legacy mode, some obsolete options are re-written into current options. .Sh SEE ALSO .Xr awk 1 , .Xr comm 1 , .Xr paste 1 , .Xr sort 1 , .Xr uniq 1 , .Xr compat 5 .Sh STANDARDS The .Nm command conforms to .St -p1003.1-2001 .