Linux administrators generally works from terminal or command line. Normally if we issue an ls command ls command will only show normal files and directories. But there are hidden files and directories where a lot of different type of data is hold. In a home directory generally hidden files are much more than normal files because most of the application creates some hidden files to store configuration, cache, history about the current users.
$ ls -a
If we want to make ls -a command default and do not want to type -a parameter every time we can create an alias like below.
$ echo "ls=ls -a" > .bashrc