MPE/iX Shell and Utilities Reference Manual, Vol 1

join(1) MPE/iX Shell and Utilities join(1)
NAME
join — join two sorted, textual relational databases
SYNOPSIS
join [–a n][–e s][–o list][–t c][–v n][–1 n][–2 n] file1 file2
join [–a n][–e s][–j[n] m][–o list][–t c] file1 file2
DESCRIPTION
join joins two databases. It assumes that both file1 and file2 contain textual databases in
which each input line is a record and that the input records are sorted in ascending order on a
particular join key field (by default the first field in each file). If you specify – in place of file1
or file2, join uses the standard input for that file.
Conceptually, join computes the Cartesian product of records from both files. By default,
spaces or tabs separate input fields and join discards any leading or trailing white space.
(There can be no white-space delimited empty input fields.) It then generates output for those
combined records in which the join key field (the first field by default) matches in each file.
The default output for join is the common join key field, followed by all the other fields in
file1, and then all the other fields in file2. The other fields from each file appear in the same
order they appeared in the original file. The default output field separator is a space character.
Options
join accepts the following options:
–a n produces an output line for lines that do not match in addition to one for a pair of
records that do match. If you specify n as one of 1 or 2, join produces unpaired
records from only that file. If you specify both –a 1 and –a 2, it produces
unpaired records from both files.
–e string
replaces empty fields (selected by –o) with string on output.
–j[n] m
uses field number m as the join key field. By default, the join key field is the first
field in each input line. As with the –a option, if n is present, this option specifies
the key field just for that file; otherwise, it specifies it for both files.
–o list ...
specifies the fields to be output. You can specify each element in list as either n.m
where n is a file number (1 or 2) and m is a field number, or as 0 (zero), which repre-
sents the join field. You can specify any number of output fields by separating them
with blanks or commas. The
POSIX-compatible form (listed first in SYNOPSIS)
requires that you specify multiple output fields as a single argument; therefore shell
quoting may be necessary. join outputs the fields in the order you list them.
1-276 Commands and Utilities