join(1) join(1)NAME join - combines (joins) two relational files SYNOPSIS join [-an] [-e string] [-jn m] [-o list] [-tc] file1 file2 ARGUMENTS -an Produces a line for each unpairable line in file n, in addition to the normal output. Replace n with a 1 or a 2 which refers to either file1 or file2, respectively. -e string Replaces empty output fields with the string s. file1 Specifies the first file to be joined with file2. file2 Specifies the second file to be joined with file1. -jn m Joins on the mth field of file n. If n is missing, use the mth field in each file. Fields are numbered starting with 1. Replace n with a 1 or a 2 which refers to either file1 or file2, respectively. -o list Causes each output line to comprise 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. The common field is not printed unless specifically requested. -tc Uses the character c as a separator (tab character). Every appearance of c in a line is significant. The character c is used as the field separator for both input and output. Note that this option must be used to preserve tabs and multiple spaces in a file. DESCRIPTION join forms, on the standard output, a join of the two relations specified by the lines of file1 and file2. If file1 is -, the standard input is used. file1 and file2 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 file1 and file2 that have identical join fields. The output line normally consists of the common field, then the rest of the line from file1, then the rest of the line from file2. January 1992 1
join(1) join(1)The default input field separators are blank, tab, or newline. In this case, multiple separators count as one field separator, and leading separators are ignored. Thus, to preserve tabs and multiple occurrences of spaces in a file, you must select tabs as the alternate delimiter using the -t option where c is the tab character (see -t option above). The default output field separator is a blank. EXAMPLES If file1 contains: Austen - Bailey - Clark - Dawson - Smith - and file2 contains: Austen Jack Anchor Brewery Clark Maryann Shoeshop Daniels Steve Computer Software Dawson Sylvia Toot Sweets Smith Sally Talcum Powdery then the command: join -j1 1 -j2 1 -o 2.2 2.1 1.2 2.3 2.4 file1 file2 will generate Jack Austen - Anchor Brewery Maryann Clark - Shoeshop Sylvia Dawson - Toot Sweets Sally Smith - Talcum Powdery The command: join -j1 4 -j2 3 -o 1.1 2.1 1.6 -t: /etc/passwd /etc/group joins the password file and the group file, matching on the numeric group ID, and the login name, the group name, and the login directory. It is assumed that the files have been sorted in ASCII collating sequence on the group ID fields. LIMITATIONS 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(1), sort(1), comm(1), uniq(1) and awk(1) are wildly incongruous. 2 January 1992
join(1) join(1)Filenames that are numeric may cause conflict when the -o option is used right before listing filenames. FILES /usr/bin/join Executable file SEE ALSO awk(1), comm(1), sort(1), uniq(1) January 1992 3