If I want to map from command ll to ls -laxo, for example.
For temporary alias, this would work: $ alias ll='ls -laxo'
To add a permanent alias, we should create .bash_profile file in the user’s home directory if it doesn't exist, and then add the alias announce to the file:
$ echo "alias ll='ls -laxo' >> ~/.bash_profile"
Don’t forget to quit Terminal and reopen it.