$>

$>

The effective uid of this process. For example:

$< = $>;            # set real to effective uid
($<,$>) = ($>,$<);  # swap real and effective uids

You can change both the effective uid and the real uid at the same time by using POSIX::setuid() . Changes to $> require a check to $! to detect any possible errors after an attempted change.

$< and $> can be swapped only on machines supporting setreuid() .

Mnemonic: it's the uid you went to, if you're running setuid.