This section describes variables that specify the programs to be used for applying patches and for computing the main difference regions (not the fine difference regions):
ediff-diff-options, it may be useful to specify options
such as ‘-w’ that ignore certain kinds of changes. However,
Ediff does not let you use the option ‘-c’, as it doesn't recognize this
diffsend to Emacs. The default is
raw-text, and this should work fine in Unix and in most cases under Windows NT/95/98/2000. There are
diffprograms for which the default option doesn't work under Windows. In such cases,
raw-text-dosmight work. If not, you will have to experiment with other coding systems or use GNU diff.
ediff-backup-extensionas described below.
Note: the -b and -z options should be specified in
ediff-backup-specs, not in
It is recommended to pass the -f option to the patch program,
so it won't
ask questions. However, some implementations don't accept this option, in
which case the default value of this variable should be changed.
Some versions of the patch program let the user specify -b extension to specify a backup file name extension. Other versions only permit -b, which (usually) assumes the extension .orig. Yet others force you to use -zextension.
ediff-backup-extension and ediff-backup-specs must
be properly set. If your patch program takes the option -b,
but not -b extension, the variable
ediff-backup-extension must still be set so Ediff will know
which extension to use.
diffprogram, it partially makes up for this drawback by letting you save the output from
diffin your preferred format, which is specified via the above two variables.
The output generated by
ediff-custom-diff-program (which doesn't
even have to be a standard-style
diff!) is not used by Ediff. It is
provided exclusively so that you can
it later, send it over email, etc. For instance, after reviewing the
differences, you may want to send context differences to a colleague.
Since Ediff ignores the ‘-c’ option in
ediff-diff-program, you would have to run
diff -c separately
just to produce the list of differences. Fortunately,
eliminate this nuisance by keeping a copy of a difference list in the
desired format in a buffer that can be displayed via the command D.