Suppose that you have a setuid program that is failing mysteriouslyand you want to see what it's doing. With normal programs you can use strace , but not even root can strace a setuid program (if you try,the program runs non-setuid).

(Yes, strace has the -u option, but it doesn't help if the setuidprogram is being run as part of a whole chain of processes in a specificenvironment and you can't just run it directly. It would be

Periodically it surprises people to learn this, but ssh is notnecessarily very fast (in the bandwidth sense). It's plenty fast fornormal interactive use, but this speed issue can matter if you aremaking large transfers with scp , rsync , or the like; depending onyour environment, ssh can go significantly slower than wire speed.

Ssh is slow because it has to encrypt and decrypt everything that goesover the wire, and this is a CPU-bound operation. How much time thistakes depends on

Suppose that you want to use some custom method of authenticating andauthorizing NFS mounts, and that your fileservers are Solaris 10 systems(although the same general approach could probably work elsewhere).Further suppose that you don't have the source to mountd , or at leastdon't want to modify it for various sensible reasons. Fortunately,there is an evil hack that you can commit that will let you do whateverauthorization checks that you need.

(When thinking about all of this, remember that NFS mount