Any idea how to create a symbolic link...for example i want to create a symbolink link for a specific user in his profile to use the df command...?

Thanks in advance

A few more details, please. After reading your posting, I am left with the impression that you're more interested in aliases (defining pseudonyms for commands) and not in creating alternate paths for files.

What i want to do is to create a directory having the commands that a specific user can execute....the only way i know is to create a directory have symbolic link of the commands that i want that user to access......

I see several possibilities here so let me take them one at a time.

1 ) Limit access to non-OS commands for a given user

You could create a directory anywhere on the system (perhaps in a "bin" subdirectory from the user's home) where commands -- compiled or script -- could be stored. Those commands could then be owned by that user and be executable only by that ID. Simply add the directory to the user's PATH environment variable.

2 ) Create a alias for a given command

This is useful when you have a particularly complicated command perhaps with many options. By using alias(1) in the user's profile, you can simplify any command. One that was standard twenty years ago when I first did this is college was:

alias la="/bin/ls -la"

3 ) I'm making this way too hard and you want the user to execute some admin commands such as df(1M)

Just add /usr/sbin to the user's PATH.

how about if i want to add a new user and give him just the same privlege as the root?....i know i am asking too much but i want to get the principle behind all this....

I'm trying to figure out the principle behind what you're asking. What problem are you trying to solve, exactly?

What i am trying to solve is this:
I have been reuested by manager to create 6 users on unix server machine. 3 users to have the same privilage as the root user(they can add/remove users, reboot or restart the server,etc...) while the rest to be normal users, (they can do daily work such as monitoring the system, cp, mv...etc)......one i was thinking to do it is to define the three new users in the root group and the rest to be in others group.....do u think this would solve the request or there is somethig else which i dont know??