|JOIN(1)||General Commands Manual||JOIN(1)|
join — relational
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.
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
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
If one of the arguments file1 or file2 is ‘-’, the standard input is used.
The options are as follows:
,’) or whitespace separated. (The latter requires quoting to protect it from the shell, or a simpler approach is to use multiple
2may be specified at the same time.
join utility exits 0 on
success, and >0 if an error occurs.
join utility is compliant with the
IEEE Std 1003.1-2008 (“POSIX.1”)
In the absence of the
historical versions of
join wrote non-matching lines
without reordering the fields. The current version writes the join field
first, followed by the remaining fields.
For compatibility with historical versions of
join, the following options are available:
joinpermitted multiple arguments to the
-ooption. These arguments were of the form “file_number.field_number” as described for the current
-ooption. This has obvious difficulties in the presence of files named “1.2”.
These options are available only so historical shell scripts don't require modification and should not be used.
join utility appeared in
Version 7 AT&T UNIX.
|January 19, 2014||OpenBSD-current|