Set Command Alias for commands often used.
1. Apply to all users.
root@debian:~# vi /etc/profile
# last line: add aliases
alias ll='ls $LS_OPTIONS -l'
alias l='ls $LS_OPTIONS -lA'
alias rm='rm -i'
alias cp='cp -i'
alias mv='mv -i'
root@debian:~# source /etc/profile # reload
2.Apply to a user
user@debian:~$ vi .bashrc
# last line: add aliases
alias ll='ls $LS_OPTIONS -l'
alias l='ls $LS_OPTIONS -lA'
alias rm='rm -i'
alias cp='cp -i'
alias mv='mv -i'
user@debian:~$ source .bashrc # reload