Diff files

Helix Core Server allows you to diff (compare) revisions of text files. By diffing files, you can display:

• Changes that you made after opening the file for edit
• Differences between any two revisions
• Differences between file revisions in different branches

To diff a file that is synced to your workspace with a depot revision, issue the p4 diff filename#rev command. If you omit the revision specifier, the file in your workspace is compared with the revision you last synced, to display changes you made after syncing it.

To diff two revisions that reside in the depot but not in your workspace, use the p4 diff2 command. To diff a set of files, specify wildcards in the filename argument when you issue the p4 diff2 command.

The p4 diff command performs the comparison on your computer, but the p4 diff2 command instructs the Helix Core Server to perform the diff and to send the results to you.

The following table lists some common uses for diff commands:

To diff	Against	Use this command
The workspace file	The head revision	p4 diff file or p4 diff file#head
The workspace file	Revision 3	p4 diff file#3
The head revision	Revision 134	p4 diff2 file file#134
File revision at changelist 32	File revision at changelist 177	p4 diff2 file@32 file@177
The workspace file	A file shelved in pending changelist 123	p4 diff file@=123
All files in release 1	All files in release 2	p4 diff2 //Acme/rel1/... //Acme/rel2/...

By default, the p4 diff command launches Helix Core Server’s internal diff application. To use a different diff program, set the P4DIFF environment variable to specify the path and executable of the desired application. To specify arguments for the external diff application, use the -d option. For details, refer to the Helix Core Command-Line (P4) Reference.