YAPD: Yet Another Perforce Diff
http://github.com/cyberguijarro/YAPD/tree/master

YAPD is a simple Python script that converts "p4 diff" command output to
regular "unified diffs" or "patches", than can be later shared and applied
in different workspaces with tools like "patch".

INSTALLATION

On UNIX-like operating systems, just copy "yapd.py" to any of the folders
in your PATH environment and rename it as you like ("yapd" is my choice).

On Windows, copy "yapd.bat" and "yapd.py" to any of the folders in your
PATH environment and correct "yapd.bat" with the right path to "yapd.py".

USAGE

yapd's syntax is:

$ yapd [-c changelist1 -c changelist2...] [file1 file2...]

File names can use Perforce wildcards as defined for "p4 opened" command.

Examples:

# Diff all opened files
$ yapd

# Diff only files in changelist 33
$ yapd -c 33

# Diff only files in folder "src"
$ yapd src/...

# Diff files in folder src within changelist 33
$ yapd -c 33 src/...

# Diff only file "main.cpp"
$ yapd main.cpp