diff(1)                          DG/UX 5.4.2                         diff(1)


NAME
       diff - differential file comparator

SYNOPSIS
       diff [ -bitw ] [ -c|-e|-f |-h|-n ] filename1 filename2
       diff [ -bitw ] [ -C number ] filename1 filename2
       diff [ -bitw ] [ -D string ] filename1 filename2
       diff [ -bitw ] [ -c|-e| -f|-h|-n ] [-l] [-r] [-s] [ -S name ]
       directory1 directory2

DESCRIPTION
       diff tells what lines must be changed in two files to bring them into
       agreement.  If filename1 (filename2) is -, the standard input is
       used.  If filename1 (filename2) is a directory, then a file in that
       directory with the name filename2 (filename1) is used.  The normal
       output contains lines of these forms:

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

       These lines resemble ed commands to convert filename1 into filename2.
       The numbers after the letters pertain to filename2.  In fact, by
       exchanging a for d and reading backward one may ascertain equally how
       to convert filename2 into filename1.  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 second file flagged by >.

       -b     Ignores trailing blanks (spaces and tabs) and treats other
              strings of blanks as equivalent.

       -i     Ignores the case of letters; for example, `A' will compare
              equal to `a'.

       -t     Expands TAB characters in output lines.  Normal or -c output
              adds character(s) to the front of each line that may adversely
              affect the indentation of the original source lines and make
              the output lines difficult to interpret.  This option will
              preserve the original source's indentation.

       -w     Ignores all blanks (SPACE and TAB characters) and treats all
              other strings of blanks as equivalent; for example,
              `if ( a == b )' will compare equal to `if(a==b)'.

       The following options are mutually exclusive:

       -c     Produces a listing of differences with three lines of context.
              With this option output format is modified slightly: output
              begins with identification of the files involved and their
              creation dates, then each change is separated by a line with a
              dozen *'s.  The lines removed from filename1 are marked with



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diff(1)                          DG/UX 5.4.2                         diff(1)


              '--'; those added to filename2 are marked '+'.  Lines that are
              changed from one file to the other are marked in both files
              with '!'.

       -C number
              Produces a listing of differences identical to that produced
              by -c with number lines of context.

       -e     Produces a script of a, c, and d commands for the editor ed,
              which will recreate filename2 from filename1.  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 the
              standard output.

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

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

       -f     Produces a similar script, not useful with ed, in the opposite
              order.

       -h     Does a fast, half-hearted job.  It works only when changed
              stretches are short and well separated, but does work on files
              of unlimited length.  Options -e and -f are unavailable with
              -h.

       -n     Produces a script similar to -e, but in the opposite order and
              with a count of changed lines on each insert or delete
              command.

       -D string
              Creates a merged version of filename1 and filename2 with C
              preprocessor controls included so that a compilation of the
              result without defining string is equivalent to compiling
              filename1, while defining string will yield filename2.

       The following options are used for comparing directories:

       -l     Produce output in long format.  Before the diff, each text
              file is piped through pr(1) to paginate it.  Other differences
              are remembered and summarized after all text file differences
              are reported.

       -r     Applies diff recursively to common subdirectories encountered.

       -s     Reports files that are the identical; these would not
              otherwise be mentioned.

       -S name
              Starts a directory diff in the middle, beginning with the file
              name.



Licensed material--property of copyright holder(s)                         2

diff(1)                          DG/UX 5.4.2                         diff(1)


FILES
       /tmp/d?????
       /usr/lib/diffh for -h
       /usr/bin/pr

DIAGNOSTICS
       Exit status is 0 for no differences, 1 for some differences, 2 for
       trouble.

SEE ALSO
       bdiff(1), cmp(1), comm(1), ed(1), pr(1).

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

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





































Licensed material--property of copyright holder(s)                         3