I'm trying to achieve this: Make my password protected SSH key expire or timeout after a while
In Yosemite, this worked fantastic, in El Capitan, using sudo, the files in /System/Libary/LaunchAgents is completely locked :( I cannot chmod, write, or chown the files.
Using Finder -> Get info, the locked checkbox is disabled for the folder and the files in it (changing owner using finder doesn't work too).