NAME
diff3 - 3-way differential file comparison

SYNOPSIS
diff3 [ -exEX3 ] file1 file2 file3

DESCRIPTION
Diff3 compares three versions of a file, and publishes disagreeing
ranges of text flagged with these codes:

==== all three files differ

====1 file1 is different

====2 file2 is different

====3 file3 is different

The type of change suffered in converting a given range of a given
file to some other is indicated in one of these ways:

f : n1 a Text is to be appended after line number n1 in file
f, where f = 1, 2, or 3.

f : n1 , n2 c Text is to be changed in the range line n1 to line
n2. If n1 = n2, the range may be abbreviated to
n1.

The original contents of the range follows immediately after a c
indication. When the contents of two files are identical, the
contents of the lower-numbered file is suppressed.

Under the -e option, diff3 publishes a script for the editor ed
that will incorporate into file1 all changes between file2 and
file3, i.e. the changes that normally would be flagged ==== and
====3. Option -x (-3) produces a script to incorporate only
changes flagged ==== (====3). The following command will apply the
resulting script to ‘file1’.

(cat script; echo ’1,$p’) | ed - file1

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

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

FILES
/tmp/d3?????
/usr/lib/diff3