comm(C)                         19 June 1992                         comm(C)


 Name

    comm - select or reject lines common to two sorted files

 Syntax

    comm [ -123 ] file1 file2

 Description

    comm reads file1 and file2, which should be ordered according to the col-
    lating sequence defined by the current locale (see sort(C)), and produces
    a three-column output: lines only in file1; lines only in file2; and
    lines in both files.  The filename ``-'' means the standard input.

    Flags 1, 2, or 3 suppress printing of the corresponding column.  Thus
    comm -12 prints only the lines common to the two files; comm -23 prints
    only lines in the first file but not in the second; comm -123 is a no-op
    (does nothing).

 See also

    cmp(C), diff(C), sort(C), uniq(C)

 Standards conformance

    comm is conformant with:

    AT&T SVID Issue 2;
    and X/Open Portability Guide, Issue 3, 1989.