How to check if “s” permission bit is set on Linux shell? or Perl?

问题

I am writing some scripts to check if the "s" permission bit is set for a particular file. For example - permissions for my file are as follows-

drwxr-s---

How can I check in bash script or a perl script if that s bit is set or not?

回答1:

If you're using perl, then have a look at perldoc:

-u  File has setuid bit set.
-g  File has setgid bit set.
-k  File has sticky bit set.

So something like:

if (-u $filename) { ... }

来源：https://stackoverflow.com/questions/29083434/how-to-check-if-s-permission-bit-is-set-on-linux-shell-or-perl