patch.1 (2010 09)

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patch(1) patch(1)

NAME

patch - program to apply a diff ﬁle to an original ﬁle

SYNOPSIS

patch [options ] orig patchﬁle [

+[ options ] orig ]

patch <patchﬁle # usual form

UNIX Standard Version

patch [-blNR][-c|-e|-n

][-d dir][-D deﬁne][

-i patchﬁle][-o outﬁle ][-p

num]

[

-r rejectﬁle ][ﬁle]

DESCRIPTION

patch will take a patch ﬁle containing any of the three forms of difference listing produced by the

diff

program (normal, context or in the style of

ed) and apply those differences to an original ﬁle, producing a

patched version. By default, the patched version is put in place of the original, with the original ﬁle

backed up to the same name with the extension

.orig, or as speciﬁed by the -b option. Note that func-

tionality of this option varies for the UNIX Standard version (see standards (5)). You may also specify

where you want the output to go with a

-o option. If patchﬁle is omitted, or is a hyphen, the patch will

be read from standard input. For the UNIX Standard (see standards (5)) version, patchﬁle has to be

speciﬁed as argument to the

-i option. If this option is omitted or a hyphen is speciﬁed as argument, the

patch will read from standard input.

Upon startup, patch will attempt to determine the type of the diff listing, unless overruled by a

-c, -e,or

-n option. Context diffs and normal diffs are applied by the

patch program itself, while ed diffs are

simply fed to the

ed editor via a pipe.

patch will try to skip any leading garbage, apply the diff, and then skip any trailing garbage. Thus you

could feed an article or message containing a diff listing to patch, and it should work. If the entire diff

is indented by a consistent amount, this will be taken into account.

With context diffs, and to a lesser extent with normal diffs,

patch

can detect when the line numbers

mentioned in the patch are incorrect, and will attempt to ﬁnd the correct place to apply each hunk of the

patch. As a ﬁrst guess, it takes the line number mentioned for the hunk, plus or minus any offset used in

applying the previous hunk. If that is not the correct place,

patch will scan both forwards and back-

wards 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 no such place is found, and it is a context diff, and the maximum fuzz factor

is set to 1 or more, then another scan takes place ignoring the ﬁrst and last line of context. If that fails,

and the maximum fuzz factor is set to 2 or more, the ﬁrst two and last two lines of context are ignored,

and another scan is made. (The default maximum fuzz factor is 2.) Note that for the UNIX Standard (see

standards (5)) version, the maximum fuzz factor can not be speciﬁed as an option, and the default max-

imum fuzz factor is used. If patch cannot ﬁnd a place to install that hunk of the patch, it will put the

hunk out to a reject ﬁle, which normally is the name of the output ﬁle plus

.rej. (Note that the rejected

hunk will come out in context diff form whether the input patch was a context diff or a normal diff. If the

input was a normal diff, many of the contexts will simply be null.) The line numbers on the hunks in the

reject ﬁle may be different than in the patch ﬁle: they reﬂect the approximate location patch thinks the

failed hunks belong in the new ﬁle rather than the old one.

As each hunk is completed, you will be told whether the hunk succeeded or failed, and which line (in the

new ﬁle)

patch thought the hunk should go on. If this is different from the line number speciﬁed in the

diff you will be told the offset. A single large offset MAY be an indication that a hunk was installed in the

wrong place. You will also be told if a fuzz factor was used to make the match, in which case you should

also be slightly suspicious. Note that the UNIX standard (see standards (5)) version does not support ver-

bose option. So, most of the diagnostic messages are not printed for this version. However user queries

will always be displayed.

If no original ﬁle is speciﬁed on the command line,

patch will try to ﬁgure out from the leading garbage

what the name of the ﬁle to edit is. In the header of a context diff, the ﬁle name is found from lines begin-

ning with *** or ---, with the shortest name of an existing ﬁle winning. Only context diffs have lines

like that, but if there is an Index: line in the leading garbage, patch will try to use the ﬁle name from

that line. The context diff header takes precedence over an Index line. If no ﬁle name can be intuited

from the leading garbage, you will be asked for the name of the ﬁle to patch.

(If the original ﬁle cannot be found, but a suitable SCCS or RCS ﬁle is handy,

patch will attempt to get

or check out the ﬁle.)

HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1

Summary of content (4 pages)

PAGE 1
patch(1) patch(1) NAME patch - program to apply a diff file to an original file SYNOPSIS patch [options ] orig patchfile [+[ options ] orig ] patch
PAGE 2
patch(1) patch(1) Additionally, if the leading garbage contains a Prereq: line, patch will take the first word from the prerequisites line (normally a version number) and check the input file to see if that word can be found. If not, patch will ask for confirmation before proceeding. The upshot of all this is that you should be able to say, while in a news interface, the following: | patch -d /usr/src/local/blurfl and patch a file in the blurfl directory directly from the article containing the patch.
PAGE 3
patch(1) patch(1) -p number sets the path name strip count, which controls how path names 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 path name. (Any intervening directory names also go away.) For example, supposing the file name in the patch file was /u/howard/src/blurfl/blurfl.
PAGE 4
patch(1) patch(1) 0 Successful completion. 1 One or more lines were written to a reject file. >1 An error occurred. For the non-UNIX Standard version, exit values vary as follows: 0 Successful completion or one or more lines were written to a reject file. 1 An error occurred. DIAGNOSTICS Most error messages indicate that patch could not parse your patch file. The message Hmm...