NAME    [Toc]    [Back]

     diff3 - 3-way differential file comparison

SYNOPSIS    [Toc]    [Back]

     diff3 [-aexEX3] file1 file2 file3

DESCRIPTION    [Toc]    [Back]

     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 separate
  versions  into a new file.  diff3 is used by rcs(1) to
merge specific
     versions or create new versions.

     The options are as follows:

     -a      Treat all files as ASCII.

     -e      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.

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

     -3       Produces  an  output script suitable for ed(1) with
changes specific
 only to file3.

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

     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 different
 between all files.

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

ENVIRONMENT    [Toc]    [Back]

     TMPDIR   If  the  environment  variable TMPDIR exists, diff3
will use the directory
 specified by TMPDIR as the temporary  directory.

FILES    [Toc]    [Back]

     /tmp/d3a.XXXXXXXXXX     temporary file
     /tmp/d3b.XXXXXXXXXX     temporary file
     /usr/libexec/diff3prog  the actual executable

SEE ALSO    [Toc]    [Back]

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

HISTORY    [Toc]    [Back]

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

BUGS    [Toc]    [Back]

     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.

OpenBSD      3.6                          April      18,     1994