random password generator in shell

random.sh

genpasswd() {
        local l=$1
        [ "$l" == "" ] && l=20
        tr -dc "A-Za-z0-9_%^&*()\`/[]{}|" < /dev/urandom | head -c ${l} | xargs
}

genpasswd 52

Here is mine:
strings /dev/urandom | grep -o '[[:alnum:]]' | head -n 30 | tr -d '\n'; echo

for additional chars:
`genpasswd() {
local l=$1
strings /dev/urandom | grep -o '[[:print:]]' | head -n ${l} | tr -d '\n'; echo
}

`

there are also powerful command line generators like "apg" (advanced password generator).