/etc/bashrc -> location where aliases and function belongs. This is the global scope
cat .bashrc -> aliases for local scope
Exemple from .bashrc -> alias rm='rm -i'
alias -> shows all aliases that exists
alias ls='ls -l'
df - information about hardware (disk free)
df -h -> return human readable format like Mbytes
alias df='df -h'
alias detele='rm -i'
unalias delete -> delete alias delete