[help-GIFT] how to patch

[Wolfgang Mueller]

Due to popular demand, how to use patch and diff:
Consider the files:

from, containing 

this line will be kept 1
this line will be kept 2
this line will be kept 3
this line will be deleted
this line will be kept 4

to, containing

this line will be kept 1
this line will be kept 2
this line will be kept 3
this line will be kept 4
this line has been added

diff -c from - < to > patch 
(The -c is important, see manpage, it gives the context to patch to
decide if the file has been patched already etc. and it gives me the
context which file to patch)
will generate the file patchtest

*** from        Fri Feb 16 11:09:29 2001
--- -   Fri Feb 16 11:16:28 2001
***************
*** 1,5 ****
  this line will be kept 1
  this line will be kept 2
  this line will be kept 3
- this line will be deleted
  this line will be kept 4
--- 1,5 ----
  this line will be kept 1
  this line will be kept 2
  this line will be kept 3
  this line will be kept 4
+ this line has been added
\ No newline at end of file

now you can use it doing

patch < patch

after that "from" will be exactly equal to "to"

If you try a second time 

patch < patch

you will get an error message telling you, that the to is already
patched and you get the choice to revert the patch.

Cheers,
Wolfgang

-- 
Wolfgang M&uuml;ller, 
assistant-doctorant ==  PhD student (2001), teaching assistant
Personal page: http://cui.unige.ch/~vision/members/WolfgangMueller.html 
Maintainer, GNU Image Finding Tool (http://www.gnu.org/software/gift)