Notification function. Add it to your .zshrc.

n

# Send notification when command has finished. 
# Usage:
#    n <command>
# 
# Lets say you want to build something that takes a certain time:
#    n make
n() {                                                                           
    "$@"                                                                        
    RETVAL=$?                                                                   
    URGENCY="normal"                                                            
    [ $RETVAL -ne 0 ] && URGENCY="critical"                                     
    notify-send -u $URGENCY -t 10000 "Command '$@' has finished"                
}