How to change /etc/auto.master to automatically mount USB pen drive soon after connecting to USB.

The auto.master file has its own manpage: man 5 auto.master.

I found a way. Tell me if there is another better way to do it.

Add the following line to /etc/auto.master (can use "vi")

/anyDirectory/anySubDirectory /etc/auto.anyname

*above "/anyDirectory/anySubDirectory" should be created.(can use "mkdir")
And add the following line to /etc/auto.anyname (you may have to create this file)

anyNameForDevice -fstype=vfat,rw :/dev/sda1


then restart autofs (can use "service autofs restart")

USB will be mounted to "/anyDirectory/anySubDirectory/anyNameForDevice" directory automatically when its pluged. this sub directory anyNameForDevice exsists only when the USB is pluged.

One thing to check is if your distro uses udev rather than autofs. Try "ps -u root | grep udev" and "sudo /sbin/chkconfig autofs".

Actually, no, that's not how autofs works. The device will be mounted when you access the mount point, not when you plug it in. Autofs mounts filesystems on demand and then automatically unmounts them after a certain period of inactivity. It doesn't know about USB hotplug events and will not respond to them. For your purposes, the difference is probably academic, but it is there.

That statement makes no sense. Udev handles dynamic creation and destruction of device nodes and is installed on every reasonably up-to-date Linux system. Autofs handles mounting local and network filesystems. One is not a substitute for the other.

I should have said udev and subfs.