''' $Header: patch.man,v 2.0 86/09/17 15:39:09 lwall Exp $ ''' ''' $Log: patch.man,v $ ''' Revision 2.0 86/09/17 15:39:09 lwall ''' Baseline for netwide release. ''' ''' Revision 1.4 86/08/01 19:23:22 lwall ''' Documented -v, -p, -F. ''' Added notes to patch senders. ''' ''' Revision 1.3 85/03/26 15:11:06 lwall ''' Frozen. ''' ''' Revision 1.2.1.4 85/03/12 16:14:27 lwall ''' Documented -p. ''' ''' Revision 1.2.1.3 85/03/12 16:09:41 lwall ''' Documented -D. ''' ''' Revision 1.2.1.2 84/12/05 11:06:55 lwall ''' Added -l switch, and noted bistability bug. ''' ''' Revision 1.2.1.1 84/12/04 17:23:39 lwall ''' Branch for sdcrdcf changes. ''' ''' Revision 1.2 84/12/04 17:22:02 lwall ''' Baseline version. ''' .de Sh .br .ne 5 .PP \fB\\$1\fR .PP .. .de Sp .if t .sp .5v .if n .sp .. ''' ''' Set up \*(-- to give an unbreakable dash; ''' string Tr holds user defined translation string. ''' Bell System Logo is used as a dummy character. ''' .ie n \{\ .tr \(bs-\*(Tr .ds -- \(bs- .if (\n(.H=4u)&(1m=24u) .ds -- \(bs\h'-12u'\(bs\h'-12u'-\" diablo 10 pitch .if (\n(.H=4u)&(1m=20u) .ds -- \(bs\h'-12u'\(bs\h'-8u'-\" diablo 12 pitch .ds L" "" .ds R" "" .ds L' ' .ds R' ' 'br\} .el\{\ .ds -- \(em\| .tr \*(Tr .ds L" `` .ds R" '' .ds L' ` .ds R' ' 'br\} .TH PATCH 1 "June 30, 1993" .SH NAME patch \- a program for applying a diff file to an original .SH SYNOPSIS .B patch [options] orig patchfile [+ [options] orig] .sp but usually just .sp .B patch sets the maximum fuzz factor. This switch only applied to context diffs, and causes .I patch to ignore up to that many lines in looking for places to install a hunk. Note that a larger fuzz factor increases the odds of a faulty patch. The default fuzz factor is 2, and it may not be set to more than the number of lines of context in the context diff, ordinarily 3. .TP 5 .B \-l causes the pattern matching to be done loosely, in case the tabs and spaces have been munged in your input file. Any sequence of whitespace in the pattern line will match any sequence in the input file. Normal characters must still match exactly. Each line of the context must still match a line in the input file. .TP 5 .B \-n forces .I patch to interpret the patch file as a normal diff. .TP 5 .B \-N causes .I patch to ignore patches that it thinks are reversed or already applied. See also .B \-R . .TP 5 .B \-o causes the next argument to be interpreted as the output file name. .TP 5 .B \-p sets the pathname strip count, which controls how pathnames found in the patch file are treated, in case the you keep your files in a different directory than the person who sent out the patch. The strip count specifies how many backslashes are to be stripped from the front of the pathname. (Any intervening directory names also go away.) For example, supposing the filename in the patch file was .sp /u/howard/src/blurfl/blurfl.c .sp setting .B \-p or .B \-p0 gives the entire pathname unmodified, .B \-p1 gives .sp u/howard/src/blurfl/blurfl.c .sp without the leading slash, .B \-p4 gives .sp blurfl/blurfl.c .sp and not specifying .B \-p at all just gives you "blurfl.c". Whatever you end up with is looked for either in the current directory, or the directory specified by the .B \-d switch. .TP 5 .B \-r causes the next argument to be interpreted as the reject file name. .TP 5 .B \-R tells .I patch that this patch was created with the old and new files swapped. (Yes, I'm afraid that does happen occasionally, human nature being what it is.) .I Patch will attempt to swap each hunk around before applying it. Rejects will come out in the swapped format. The .B \-R switch will not work with ed diff scripts because there is too little information to reconstruct the reverse operation. .Sp If the first hunk of a patch fails, .I patch will reverse the hunk to see if it can be applied that way. If it can, you will be asked if you want to have the .B \-R switch set. If it can't, the patch will continue to be applied normally. (Note: this method cannot detect a reversed patch if it is a normal diff and if the first command is an append (i.e. it should have been a delete) since appends always succeed, due to the fact that a null context will match anywhere. Luckily, most patches add or change lines rather than delete them, so most reversed normal diffs will begin with a delete, which will fail, triggering the heuristic.) .TP 5 .B \-s makes .I patch do its work silently, unless an error occurs. .TP 5 .B \-S causes .I patch to ignore this patch from the patch file, but continue on looking for the next patch in the file. Thus .sp patch -S + -S + sets internal debugging flags, and is of interest only to .I patch patchers. .SH ENVIRONMENT No environment variables are used by .IR patch . .SH FILES /tmp/patch* .SH SEE ALSO diff(1) .SH NOTES FOR PATCH SENDERS There are several things you should bear in mind if you are going to be sending out patches. First, you can save people a lot of grief by keeping a patchlevel.h file which is patched to increment the patch level as the first diff in the patch file you send out. If you put a Prereq: line in with the patch, it won't let them apply patches out of order without some warning. Second, make sure you've specified the filenames right, either in a context diff header, or with an Index: line. If you are patching something in a subdirectory, be sure to tell the patch user to specify a .B \-p switch as needed. Third, you can create a file by sending out a diff that compares a null file to the file you want to create. This will only work if the file you want to create doesn't exist already in the target directory. Fourth, take care not to send out reversed patches, since it makes people wonder whether they already applied the patch. Fifth, while you may be able to get away with putting 582 diff listings into one file, it is probably wiser to group related patches into separate files in case something goes haywire. .SH DIAGNOSTICS Too many to list here, but generally indicative that .I patch couldn't parse your patch file. .PP The message \*(L"Hmm...\*(R" indicates that there is unprocessed text in the patch file and that .I patch is attempting to intuit whether there is a patch in that text and, if so, what kind of patch it is. .SH CAVEATS .I Patch cannot tell if the line numbers are off in an ed script, and can only detect bad line numbers in a normal diff when it finds a \*(L"change\*(R" or a \*(L"delete\*(R" command. A context diff using fuzz factor 3 may have the same problem. Until a suitable interactive interface is added, you should probably do a context diff in these cases to see if the changes made sense. Of course, compiling without errors is a pretty good indication that the patch worked, but not always. .PP .I Patch usually produces the correct results, even when it has to do a lot of guessing. However, the results are guaranteed to be correct only when the patch is applied to exactly the same version of the file that the patch was generated from. .SH BUGS Could be smarter about partial matches, excessively \&deviant offsets and swapped code, but that would take an extra pass. .PP If code has been duplicated (for instance with #ifdef OLDCODE ... #else ... #endif), .I patch is incapable of patching both versions, and, if it works at all, will likely patch the wrong one, and tell you that it succeeded to boot. .PP If you apply a patch you've already applied, .I patch will think it is a reversed patch, and offer to un-apply the patch. This could be construed as a feature.