diff(1)                             CLIX                             diff(1)



  NAME

    diff - Runs a differential file comparator

  SYNOPSIS

    diff [-efbh] file1 file2

  FLAGS

    -b   Causes trailing blanks (spaces and tabs) to be ignored and other
         strings of blanks to compare equal.

    -e   Produces a script of a, c, and d commands for the editor ed, which
         will recreate file2 from file1.

    -f   Produces a script similar to the -e flag, in the opposite order.
         This script is not useful with ed.  In connection with -e, the
         following shell program may help maintain multiple versions of a
         file.  Only an ancestral file ($1) and a chain of version-to-version
         ed scripts ($2, $3, ... ) made by diff need be on hand.  A ``latest
         version'' appears on stdout.

         (shift; cat $*; echo '1,$p')|ed - $1

         Except in rare circumstances, diff finds a smallest sufficient set of
         file differences.

    -h   Performs a fast comparison.  This flag works only when changed
         stretches are short and well separated, but it works on files of
         unlimited length.  The -e and -f are unavailable with -h.

  DESCRIPTION

    The diff command tells what lines must be changed in two files to bring
    them into agreement.  If file1 (file2) is -, stdin is used.  If file1
    (file2) is a directory, then a file in that directory with the name file2
    (file1) is used.  The normal output contains lines of these forms:

    nl a n3, n4
    n1,n2 d n3
    n1,n2 c n3,n4

    These lines resemble ed commands to convert file1 into file2.  The numbers
    after the letters pertain to file2.  In fact, by exchanging a for d and
    reading backward one may ascertain equally how to convert file2 into
    file1.  As in ed, identical pairs, where n1 = n2 or n3 = n4, are
    abbreviated as a single number.

    Following each of these lines come all the lines that are affected in the
    first file flagged by <, then all the lines that are affected in the



  2/94 - Intergraph Corporation                                              1

  diff(1)                             CLIX                             diff(1)



    second file flagged by >.

  EXAMPLES

    Given the following two files:  file1:

    Oh, give me
     a home
    where the
     buffalo roam

    file2:

    Oh, give me
     land, lotsa land,
    where the
                  buffalo roam

    Entering the command

    diff file1 file2

    produces the following output:

    2c2
    <  a home
    ---
    >  land, lotsa land,
    4c4
    <  buffalo roam
    ---
    >             buffalo roam

    The command

    diff -b file1 file2

    produces the following output:

    2c2
    <  a home
    ---
    >  land, lotsa land,

    Note that the last line, which differed only in spaces, is considered the
    same with the -b flag.

    Entering the command

    diff -e file1 file2




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  diff(1)                             CLIX                             diff(1)



    will produce the following:

    4c
            buffalo roam
    2c
     land, lotsa land,

    This output can be used as an ed script.

  FILES

    /tmp/d?????

    /usr/lib/diffh
           for -h

  NOTES

    Editing scripts produced under the -e or -f flag are naive about creating
    lines consisting of a single dot (.).

  DIAGNOSTICS

    Missing newline at end of file X
           Indicates that the last line of file X did not have a newline.  If
           the lines are different, they will be flagged and output; although
           the output will seem to indicate they are the same.

    diff: files too big, try -h
           Indicates that the files being processed are too big for diff to
           process.  Using -h will work with any size file, but is less
           useful.

  EXIT VALUES

    The exit status for diff is as follows:

    0   No differences exist.

    1   Some differences exist.

    2   Trouble has occurred.

  RELATED INFORMATION

    Commands: bdiff(1), cmp(1), comm(1), ed(1)








  2/94 - Intergraph Corporation                                              3