3-way differential file
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:
- Produces an output script suitable for ed(1) with changes specific only to file3.
- Treat all files as ASCII.
- Similar to
-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.
- Produces output in a form suitable as an input script for the
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
-eoption 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.
- Produces an output script suitable for ed(1) with changes specific only to all three versions.
-E option is used by RCS
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.
- The lines beneath this notation are ranges of lines which are exclusively different in file n.
- If the environment variable
diff3will use the directory specified by
TMPDIRas the temporary directory.
- temporary file
- temporary file
- the actual executable
diff(1), ed(1), merge(1), rcs(1), sdiff(1)
diff3 command appeared in
Version 7 AT&T UNIX.
-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