sort - sort lines of text files

sort -r file

sort -n file

sort -M file

sort -k 1 file

sort -t ':' -k 3 -n /etc/passwd

sort -f file

sort -u file

sort - sort lines of text files

alias -p

type cd

cd is a shell builtin

type ps

ps is hashed (/usr/bin/ps)

type -a echo

echo is a shell builtin
echo is /usr/bin/echo
echo is /bin/echo

type ll

ll is aliased to `ls -alF'

type -a ls

ls is aliased to `ls --color=auto'
ls is /usr/bin/ls
ls is /bin/ls

readlink - print resolved symbolic links or canonical file names

readlink -f /bin/vim

/usr/bin/vim.basic