Please compare the following two lines:-rws---r-x 1 root root 21872 2009-10-13 21:06 prg1 -rwx---r-x 1 root root 21872 2009-10-13 21:06 prg2 Does the setuid bit on prg1, along with the read and execute bits for 'other' mean that any user can run it with root privileges?  The  prg2 also has read and execute for 'other', but does not have the setuid bit set, so does that mean it can still be run by any user but without root privileges?
What does the 's' attribute in file permissions mean?
privileges;setuid
Precisely the opposite, you don't need to use sudo or switch to root, the executable does it for you.