Mysterious line in perl

I am reviewing some perl code and ran across this line

$> = $<;

It's older code and I wish I could have been more descriptive in the title above (sorry folks). What does this 开发者_如何学Goline do?

It sets the effective user id to the real user id.

Spig is correct. There are a whole whack of other global variables whose name is only a symbol. You might find it useful to check perldoc perlvar for a list of them and what they mean.