JOIN(1) — USER COMMANDS
NAME
join − relational database operator
SYNOPSIS
join [ −an ] [ −e string ] [ −j[1|2] m ] [ −o list ] [ −tc ] filename1 filename2
DESCRIPTION
join forms, on the standard output, a join of the two relations specified by the lines of filename1 and filename2. If filename1 is ‘−’, the standard input is used.
File1 and filename2 must be sorted in increasing ASCII collating sequence on the fields on which they are to be joined, normally the first in each line.
There is one line in the output for each pair of lines in filename1 and filename2 that have identical join fields. The output line normally consists of the common field, then the rest of the line from filename1, then the rest of the line from filename2.
Fields are separated by blanks, tabs or newlines. Multiple separators count as one, and leading separators are discarded.
OPTIONS
−an The parameter n can be one of the values:
1produce a line for each unpairable line in filename1.
2produce a line for each unpairable line in filename2.
3produce a line for each unpairable line in both filename1 and filename2.
The normal output is also produced.
−e s Replace empty output fields by string.
−j[1|2] m
The j may be immediately followed by n, which is either a ‘1’ or a ‘2’. If n is missing, the join is on the m’th field of both files. If n is present, the join is on the m’th field of file n, and the first field of the other. Note that join counts fields from 1 instead of 0 like sort does.
−o list
Each output line comprises the fields specified in list, each element of which has the form n.m, where n is a file number and m is a field number. Note that join counts fields from 1 instead of 0 like sort does.
−tc Use character c as a separator (tab character). Every appearance of c in a line is significant.
SEE ALSO
sort(1), comm(1), awk(1), uniq(1), look(1)
BUGS
With default field separation, the collating sequence is that of sort −b; with −t, the sequence is that of a plain sort.
The conventions of join, sort, comm, uniq, look, and awk are wildly incongruous.
Sun Release 3.0β — Last change: 23 September 1985