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(diff.info)diff3 Hunks

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`diff3' Hunks
=============

   Groups of lines that differ in two or three of the input files are
called "diff3 hunks", by analogy with `diff' hunks (Note: Hunks).  If
all three input files differ in a `diff3' hunk, the hunk is called a
"three-way hunk"; if just two input files differ, it is a "two-way
hunk".

   As with `diff', several solutions are possible.  When comparing the
files `A', `B', and `C', `diff3' normally finds `diff3' hunks by
merging the two-way hunks output by the two commands `diff A B' and
`diff A C'.  This does not necessarily minimize the size of the output,
but exceptions should be rare.

   For example, suppose `F' contains the three lines `a', `b', `f', `G'
contains the lines `g', `b', `g', and `H' contains the lines `a', `b',
`h'.  `diff3 F G H' might output the following:

     ====2
     1:1c
     3:1c
       a
     2:1c
       g
     ====
     1:3c
       f
     2:3c
       g
     3:3c
       h

because it found a two-way hunk containing `a' in the first and third
files and `g' in the second file, then the single line `b' common to
all three files, then a three-way hunk containing the last line of each
file.