join

join [options] file1 file2

Join the common lines of sorted file1 and sorted file2. (Read standard input if file1 is -.) The output contains the common field and the remainder of each line from file1 and file2. In the options below, n can be 1 or 2, referring to file1 or file2.

Options

-an

List unpairable lines in file n (or both if n is omitted).

-e s

Replace any empty output field with the string s.

-jn m

Join on the mth field of file n (or both files if n is omitted).

-o n.m

Each output line contains fields specified by file number n and field number m. The common field is suppressed unless requested.

-tc

Use character c as field separator for input and output.

Examples

Assuming the following input files:

% cat score
olga    81      91
rene    82      92
zack    83      93
% cat grade
olga    B       A
rene    B       A

List scores followed by grades, including unmatched lines:

% join -a score grade
olga 81 91 B A
rene 82 92 B A
zack 83 93

Pair each score with its grade:

% join -o 1.1 1.2 2.2 1.3 2.3 score grade
olga 81 B 91 A
rene 82 B 92 A