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Perforce 2009.1: Command Reference



p4 diff2
Synopsis
Compare two depot file revisions.
Syntax
p4 [g-opts] diff2 [-dflags -q -t -u] file1[rev] file2[rev]
p4 [g-opts] diff2 [-dflags -q -t -u] -b branch [[fromfile[rev]] tofile[rev]]
Description
p4 diff2 uses the Perforce server's built-in diff routine to compare two file revisions from the depot. These revisions are usually two versions of the same file, but they can be revisions of entirely separate files. If no file revision is explicitly provided with the file argument, the head revision is used.
p4 diff2 does not use the diff program specified by the environment variable P4DIFF. The diff algorithm used by p4 diff2 runs on the machine hosting the Perforce server, and always uses the server's built-in diff routine.
You can specify file patterns as arguments in place of specific files, with or without revision specifiers; this causes Perforce to perform multiple diffs for each pair of files that match the given pattern. If you invoke p4 diff2 with file patterns, escape the file patterns from the OS shell by using quotes or backslashes, and be sure that the wildcards in the two file patterns match.
Perforce presents the diffs in UNIX diff format, prepended with a header. The header is formatted as follows:
==== file1 (filetype1) - file2 (filetype2) ==== summary
The possible values and meanings of summary are:
content: the file revisions' contents are different,
types: the revisions' contents are identical, but the filetypes are different,
identical: the revisions' contents and filetypes are identical.
If either file1 or file2 does not exist at the specified revision, the header will display the summary as <none>.
Options
Quiet diff. Display only the header, and don't even display that when the file revisions' contents and types are identical.
-dflags
Runs the diff routine with one of a subset of the standard UNIX diff flags. See the Usage Notes below for a listing of these flags.
Use a branch specification to diff files in two branched codelines. The files that are compared can be limited by file patterns in either fromfile or tofile.
Generate unified output format, showing added and deleted lines with sufficient context for compatibility with the patch(1) utility. Only those files that differ are included. File names and dates remain in Perforce syntax.
Usage Notes
Can File Arguments Use
Revision Specifier?
read access necessary
for both file revisions
RCS output format, showing additions and deletions made to the file and associated line ranges.
unified output format, showing added and deleted lines with sufficient context for compatibility with the patch(1) utility.
p4 diff2 -dub file1 file2
specifies a unified diff that ignores changes in whitespace.
The header line of a unified diff produced with the -du option for patch(1) use displays the diffed files in Perforce syntax, not local syntax.
When p4 diff2 is used to diff binary files, the line
... files differ ...
is printed if they are not identical.
The option -b branch [ [fromfile[rev]] tofile[rev] ] may seem incorrect at first. Since the branch specification maps fromfiles to tofiles, why would you specify both fromfile and tofile file patterns? You wouldn't, but this syntax allows you to specify a fromfile file pattern and a tofile revision, or a fromfile revision and a tofile file pattern.
Examples
Compare the second revision of file file to its head revision, and display a summary of what chunks were added to, deleted from, or changed within the file.
p4 diff2
file@34 file@1998/12/04
Diff the revision of file that was in the depot after changelist 34 was submitted against the revision in the depot at midnight on December 4, 1998.
p4 diff2
//depot/rel1/... //depot/rel2/...#4
Compare the head revisions of all files under //depot/rel1 to the fourth revision of all files under //depot/rel2
p4 diff2
//depot/rel1/* //depot/rel2/...
p4 diff2
-b branch2 //depot/rel2/...#2 @50
Compare the second revision of the files in //depot/rel2/... to the files branched from it by branch specification branch2 at the revision they were at in changelist 50.
Related Commands


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Perforce 2009.1: Command Reference
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