1.\" Copyright (c) 1990, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the Institute of Electrical and Electronics Engineers, Inc. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. All advertising materials mentioning features or use of this software 16.\" must display the following acknowledgement: 17.\" This product includes software developed by the University of 18.\" California, Berkeley and its contributors. 19.\" 4. Neither the name of the University nor the names of its contributors 20.\" may be used to endorse or promote products derived from this software 21.\" without specific prior written permission. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33.\" SUCH DAMAGE. 34.\" 35.\" @(#)join.1 8.3 (Berkeley) 4/28/95 36.\" $FreeBSD$ 37.\" 38.Dd April 18, 2002 39.Dt JOIN 1 40.Os 41.Sh NAME 42.Nm join 43.Nd relational database operator 44.Sh SYNOPSIS 45.Nm 46.Oo 47.Fl a Ar file_number | Fl v Ar file_number 48.Oc 49.Op Fl e Ar string 50.Op Fl o Ar list 51.Bk -words 52.Ek 53.Op Fl t Ar char 54.Op Fl \&1 Ar field 55.Op Fl \&2 Ar field 56.Ar file1 57.Ar file2 58.Sh DESCRIPTION 59The 60.Nm 61utility performs an 62.Dq equality join 63on the specified files 64and writes the result to the standard output. 65The 66.Dq join field 67is the field in each file by which the files are compared. 68The first field in each line is used by default. 69There is one line in the output for each pair of lines in 70.Ar file1 71and 72.Ar file2 73which have identical join fields. 74Each output line consists of the join field, the remaining fields from 75.Ar file1 76and then the remaining fields from 77.Ar file2 . 78.Pp 79The default field separators are tab and space characters. 80In this case, multiple tabs and spaces count as a single field separator, 81and leading tabs and spaces are ignored. 82The default output field separator is a single space character. 83.Pp 84Many of the options use file and field numbers. 85Both file numbers and field numbers are 1 based, i.e. the first file on 86the command line is file number 1 and the first field is field number 1. 87The following options are available: 88.Bl -tag -width indent 89.It Fl a Ar file_number 90In addition to the default output, produce a line for each unpairable 91line in file 92.Ar file_number . 93.It Fl e Ar string 94Replace empty output fields with 95.Ar string . 96.It Fl o Ar list 97The 98.Fl o 99option specifies the fields that will be output from each file for 100each line with matching join fields. 101Each element of 102.Ar list 103has the either the form 104.Ql file_number.field , 105where 106.Ar file_number 107is a file number and 108.Ar field 109is a field number, or the form 110.Ql 0 111.Pq zero , 112representing the join field. 113The elements of list must be either comma 114.Pq Dq \&, 115or whitespace separated. 116(The latter requires quoting to protect it from the shell, or, a simpler 117approach is to use multiple 118.Fl o 119options.) 120.It Fl t Ar char 121Use character 122.Ar char 123as a field delimiter for both input and output. 124Every occurrence of 125.Ar char 126in a line is significant. 127.It Fl v Ar file_number 128Do not display the default output, but display a line for each unpairable 129line in file 130.Ar file_number . 131The options 132.Fl v Ar 1 133and 134.Fl v Ar 2 135may be specified at the same time. 136.It Fl 1 Ar field 137Join on the 138.Ar field Ns 'th 139field of file 1. 140.It Fl 2 Ar field 141Join on the 142.Ar field Ns 'th 143field of file 2. 144.El 145.Pp 146When the default field delimiter characters are used, the files to be joined 147should be ordered in the collating sequence of 148.Xr sort 1 , 149using the 150.Fl b 151option, on the fields on which they are to be joined, otherwise 152.Nm 153may not report all field matches. 154When the field delimiter characters are specified by the 155.Fl t 156option, the collating sequence should be the same as 157.Xr sort 1 158without the 159.Fl b 160option. 161.Pp 162If one of the arguments 163.Ar file1 164or 165.Ar file2 166is 167.Dq - , 168the standard input is used. 169.Sh DIAGNOSTICS 170.Ex -std 171.Sh COMPATIBILITY 172For compatibility with historic versions of 173.Nm , 174the following options are available: 175.Bl -tag -width indent 176.It Fl a 177In addition to the default output, produce a line for each unpairable line 178in both file 1 and file 2. 179.It Fl j1 Ar field 180Join on the 181.Ar field Ns 'th 182field of file 1. 183.It Fl j2 Ar field 184Join on the 185.Ar field Ns 'th 186field of file 2. 187.It Fl j Ar field 188Join on the 189.Ar field Ns 'th 190field of both file 1 and file 2. 191.It Fl o Ar list ... 192Historical implementations of 193.Nm 194permitted multiple arguments to the 195.Fl o 196option. 197These arguments were of the form 198.Ql file_number.field_number 199as described 200for the current 201.Fl o 202option. 203This has obvious difficulties in the presence of files named 204.Ql 1.2 . 205.El 206.Pp 207These options are available only so historic shellscripts don't require 208modification and should not be used. 209.Sh STANDARDS 210The 211.Nm 212command conforms to 213.St -p1003.1-2001 . 214.Sh SEE ALSO 215.Xr awk 1 , 216.Xr comm 1 , 217.Xr paste 1 , 218.Xr sort 1 , 219.Xr uniq 1 220