Please follow the below steps to disable a specific command(s) for a certain user.
# su – riyesh
$ which rm (Here rm command as an example)
$ mkdir ~/bin
$ ln -s /bin/* ~/bin/ (/bin is the PATH for rm)
$ rm -rf ~/bin/rm
Take the output of $PATH for this user
$ echo $PATH > …

ltiple Shell login by the same user on a Linux box you have to set a maximum number of logins in /etc/security/limits.conf for a user or a group.
For example:
# groupadd salesgroup
# useradd -G salesgroup salesman1
# useradd -G salesgroup salesmanager
# echo “@salesgroup – maxlogins 10? >> /etc/security/limits.conf
# echo “salesman1 – maxlogins 5? >> …