To make sure they are in the place you expect them to be, you could make use of the -x function. However, don't expect all those tools to be in /bin. You'll find some of them in /bin, others in /usr/bin. Or in both. And sometimes, /bin is just a symlink to /usr/bin.

sqlplus and gtar should not be found in /bin or /usr/bin. But you may however just depend on the users PATH. Aliases don't play a role - if a shell is being used, it will be the Bourne shell, and that doesn't have aliases.

Abigail