Node:Inexact, Next:Dry Runs, Previous:Reversed Patches, Up:Imperfect
patch
Find Inexact MatchesFor context diffs, and to a lesser extent normal diffs, patch
can
detect when the line numbers mentioned in the patch are incorrect, and
it attempts to find the correct place to apply each hunk of the patch.
As a first guess, it takes the line number mentioned in the hunk, plus
or minus any offset used in applying the previous hunk. If that is not
the correct place, patch
scans both forward and backward for a
set of lines matching the context given in the hunk.
First patch
looks for a place where all lines of the context
match. If it cannot find such a place, and it is reading a context or
unified diff, and the maximum fuzz factor is set to 1 or more, then
patch
makes another scan, ignoring the first and last line of
context. If that fails, and the maximum fuzz factor is set to 2 or
more, it makes another scan, ignoring the first two and last two lines
of context are ignored. It continues similarly if the maximum fuzz
factor is larger.
patch
usually produces the correct results, even when it must
make many guesses. However, the results are guaranteed only when
the patch is applied to an exact copy of the file that the patch was
generated from.