To make aliases of OSX/Unix commands in your bash shell on OS X 10.9, 10.8 and 10.7, it is done via your .bash_profile file which lives in your home account directory, if the file does not already exist, just create one.

Launch Terminal from the /Application/Utilities folder

Go to your home directory by just entering cd followed by the ‘return’ key to enter the command:

cd

List your home directory contents including invisible files to see if the file already exists, use:

ls -la

drwxr-xr-x+ 18 ladmin staff 612 Jul 14 09:21 .
drwxr-xr-x 6 root admin 204 Jul 3 18:28 ..
-rw------- 1 ladmin staff 3 Jun 2 12:53 .CFUserTextEncoding
-rw-r--r--@ 1 ladmin staff 6148 Jul 14 09:01 .DS_Store
drwx------ 5 ladmin staff 170 Jul 3 18:44 .Trash
-rw------- 1 ladmin staff 1157 Jul 14 08:59 .bash_history
drwx------+ 5 ladmin staff 170 Jul 14 08:33 Desktop
drwx------+ 6 ladmin staff 204 Jun 2 13:48 Documents
drwx------+ 8 ladmin staff 272 Jul 3 18:10 Downloads
drwx------+ 29 ladmin staff 986 Jul 3 17:49 Library
drwx------+ 3 ladmin staff 102 Jun 2 12:53 Movies
drwx------+ 3 ladmin staff 102 Jun 2 12:53 Music
drwx------+ 4 ladmin staff 136 Jun 2 12:53 Pictures
drwxr-xr-x+ 4 ladmin staff 136 Jun 2 12:53 Public
drwxr-xr-x+ 6 ladmin staff 204 Jul 3 18:11 Sites

Create the .bash_profile file using the command line program called ‘nano’ if it doesn’t exist:

nano .bash_profile

When the file is created you are ready to enter your alias commands.
So here I am using the alias ‘l’ to alias the command ‘ls -lah’

alias l='ls -lah'

In nano ‘control+o’ to write the file out and ‘control+x’ to exit the file.

Refresh the bash shell environment:

source ~/.bash_profile

That’s it, now the alias will take effect.

To add other aliases just start a new line,  and apply the same formatting.