shuf -i 1-10 -n1
    10

    shuf -n1 /usr/share/dict/usa 
    saltier

    # random 24 char
    base64 /dev/urandom | tr -d '/+' | dd bs=24 count=1 2>/dev/null;echo
    5seFtWG09vTUc0VCMb3BJ6Al

    # random letter
    base64 /dev/urandom | tr -d '/+' | sed s/[^[:alpha:]]//g | tr 'A-Z' 'a-z' | dd bs=1 count=1 2>/dev/null;echo
    x

    # bash
    echo $RANDOM
    21178