diff3(1) - NetBSD Manual Pages

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DIFF3(1)                NetBSD General Commands Manual                DIFF3(1)


NAME

     diff3 -- 3-way differential file comparison


SYNOPSIS

     diff3 [-3AaEeimTXx] [--diff-program program] [--strip-trailing-cr]
           [-L | --label label1] [-L | --label label2] [-L | --label label3]
           file1 file2 file3
     diff3 [--help] [--version]


DESCRIPTION

     The diff3 utility compares the contents of three different versions of a
     file, file1, file2 and file3, writing the result to the standard output.
     The options describe different methods of merging and purging the sepa-
     rate versions into a new file.  diff3 is used by rcs(1) to merge specific
     versions or create new versions.

     The options are as follows:

     -3, --easy-only
             Produces an output script suitable for ed(1) with changes spe-
             cific only to file3.

     -A --show-all
             Output all changes, bracketing conflicts.

     -a, --text
             Treat all files as ASCII.

     -E, --show-overlap

     -X      Similar to -e and -x, respectively, but treat overlapping changes
             (i.e., changes that would be noted with ==== in the normal list-
             ing) differently.  The overlapping lines from both files will be
             inserted by the edit script, bracketed by "<<<<<<" and ">>>>>>"
             lines.

     -e, --ed
             Produces output in a form suitable as an input script for the
             ed(1) utility.  The script may then be used to merge differences
             common between all three files and differences specific to file1
             and file3.  In other words, the -e option ignores differences
             specific to file1 and file2, and those specific to file2 and
             file3.  It is useful for backing out changes specific to file2
             only.

     --help  Prints usage information and exits.

     -i      Appends 'w' and 'q' ed(1) commands.

     -L, --label
             Defines labels to print instead of file names file1, file2 and
             file3.

     -m, --merge
             Merge output instead of generating ed script.

     -T, --initial-tab
             In the normal listing, use a tab instead of two spaces at the
             beginning of each line.  In modes that produce an ed(1) script,
             this option changes nothing.

     -x, --overlap-only
             Produces an output script suitable for ed(1) with changes spe-
             cific only to all three versions.

     --diff-program program
             Use program instead of the default diff(1) to compare files.

     --strip-trailing-cr
             Strip trailing carriage return on input files.

     --version
             Prints version information and exits.

     The -E option is used by RCS merge(1) to ensure that overlapping changes
     in the merged files are preserved and brought to someone's attention.

     For example, suppose lines 7-8 are changed in both file1 and file2.
     Applying the edit script generated by the command

           $ diff3 -E file1 file2 file3

     to file1 results in the file:

           lines 1-6
           of file1
           <<<<<<< file1
           lines 7-8
           of file1
           =======
           lines 7-8
           of file3
           >>>>>>> file3
           rest of file1

     The default output of diff3 makes notation of the differences between all
     files, and those differences specific to each pair of files.  The changes
     are described by the commands necessary for ed(1) to create the desired
     target from the different versions.  See diff(1) for a description of the
     commands.

     ====   The lines beneath this notation are ranges of lines which are dif-
            ferent between all files.

     ====n  The lines beneath this notation are ranges of lines which are
            exclusively different in file n.


SEE ALSO

     diff(1), ed(1), merge(1), rcs(1), sdiff(1)


HISTORY

     A diff3 command appeared in Version 7 AT&T UNIX.


BUGS

     The -e option cannot catch and change lines which have `.' as the first
     and only character on the line.  The resulting script will fail on that
     line as `.' is an ed(1) editing command.

NetBSD 11.99                     June 23, 2022                    NetBSD 11.99