glenda.party
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JOIN(1)                     General Commands Manual                    JOIN(1)



NAME
       join - relational database operator

SYNOPSIS
       join [ options ] file1 file2

DESCRIPTION
       Join  forms, on the standard output, a join of the two relations speci‐
       fied by the lines of file1 and file2.  If one of the file names 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  con‐
       sists  of  the common field, then the rest of the line from file1, then
       the rest of the line from file2.

       Input fields are normally separated spaces or tabs;  output  fields  by
       space.   In  this  case,  multiple separators count as one, and leading
       separators are discarded.

       The following options are recognized, with POSIX syntax.

       -a n   In addition to the normal output, produce a line  for  each  un‐
              pairable line in file n, where n is 1 or 2.

       -v n   Like -a, omitting output for paired lines.

       -e s   Replace empty output fields by string s.

       -1 m
       -2 m   Join on the mth field of file1 or file2.

       -jn m  Archaic equivalent for -n m.

       -ofields
              Each  output  line  comprises the designated fields.  The comma-
              separated field designators  are  either  0,  meaning  the  join
              field, or have the form n.m, where n is a file number and m is a
              field number.  Archaic usage allows separate arguments for field
              designators.

       -tc    Use  character  c as the only separator (tab character) on input
              and output.  Every appearance of c in a line is significant.

EXAMPLES
       sort /adm/users | join -t: -a 1 -e "" - bdays
              Add birthdays to password information, leaving unknown birthdays
              empty.   The  layout  of  is  given  in users(6); bdays contains
              sorted lines like

       tr : ' ' </adm/users | sort -k 3 3 >temp
       join -1 3 -2 3 -o 1.1,2.1 temp temp | awk '$1 < $2'
              Print all pairs of users with identical userids.

SOURCE
       /sys/src/cmd/join.c

SEE ALSO
       sort(1), comm(1), awk(1)

BUGS
       With default field separation, the collating sequence is that  of  sort
       -b -ky,y; with -t, the sequence is that of sort -tx -ky,y.
       One of the files must be randomly accessible.




                                                                       JOIN(1)