does GPIO button handler work on 6.5.2

[avior]

thank you tim for fast reply
i got the following buttons to work 

toggle using "mpc, toggle"
next            "mpc, next"
prev            "mpc prev"
turn off        "sudo, poweroff"


but where do i put the comma in:
but cant Figure out the volume up and down 

/var/www/vol.sh up 10
/var/www/vol.sh dn 10

thank you