Sometimes you might need to apply a diff from another source to a tree under Perforce control. If it is a large diff that affects lots of files, it might be inconvenient to manually run p4 edit on each file. There is a trick for making this easier. First, make sure that no files are open on your client and that your tree is synced and up to date. Then apply the diff using the normal tools, and coerce the permissions on the files if needed. Then run the following commands:

% p4 diff -se ... | xargs p4 edit
% p4 diff -sd ... | xargs p4 delete
% find . -type f | xargs p4 add

The first command tells Perforce to look for files that have changed, even if they are not open. The second command tells Perforce to look for files that no longer exist on the local machine but do exist on the server. The third command then attempts to add all of the files that it can find locally. This is a very brute-force method, but it works because Perforce will only add the files that it does not already know about. The result of running these commands will be a set of files that are opened for edit, removal, or add, as appropriate.

Verify the active changelist with:

% p4 changelist
% p4 diff -du

and just do a p4 submit after that.