How to add alias on Mac(It's common for most system)

Since these files are hidden you will have to do an ls -a to list them. If you don't have one you can create one.

Update:

If I remember correctly, when I had bought my mac, .bash_login file wasn't there. I had to create it for myself so that I could put prompt info, alias, functions etc in it. Here are the steps if you would like to create one -

1. Start up Terminal
2. Type cd ~/ to go to your home folder
3. Type touch .bash_profile to create your new file.
4. Edit .bash_profile with your favorite editor (or you can just type open -e .bash_profile to open it in TextEdit.
5. Type . .bash_profile to reload .bash_profile and update any alias you add.

Another covenient way:

The config file for scripts and programs is ~/.bashrc and the config file that gets loaded when you use Terminal is ~/.bash_login.

I think the best way is to just have everything in ~/.bashrc.

For your specific question just enter (this will overwrite any existing ~/.bashrc):

echo "alias blah="/usr/bin/blah"" >~/.bashrc

into the Terminal and a ~/.bashrc file will be created with your new alises. After that just edit the file to add new aliases, functions, settings etc.