To define a command alias in LINUX OS, follow these steps,
1. open bashrc script for the user you want to set command alias:
For example: su - test1
test1$vi ~/.bashrc
Now add your commands alias at the end of the file:
alias stopapache='/u01/apache/2.4/bin/apachectl stop'
alias startapache='/u01/apache/2.4/bin/apachectl start'
alias statusapache='/u01/apache/2.4/bin/apachectl status'
Now to reload your profile either logout and login back or you can run following command to reload bashrc scripts quickly while logged in:
source ~/.bashrc