how can i know which device is which in /dev

vijaya_svk · 01-14-2009, 01:25 PM

Hi
I am having a doubt that when i see /dev directory, i found all the devices that are attached to the system, But how can i identify specific device in the list.??

For suppose i see tty------tty0 to tty68. Now how can i know what are all these devices?? about 70 devices are there in the entry. how can i identify them. Just by seeing the MAJOR number same for all those i can come to a conclusion that all are using the same driver, but according to the MINOR number how can i identify???

PTrenholme · 01-14-2009, 03:26 PM

I'm not sure what you're asking, but most of the "devices" in /dev are just placeholders for use when needed. If you're asking "Which tty entries are currently in use," something like this would tell you.

Code:

$ ps -ea | grep tty
 2599 tty4     00:00:00 mingetty
 2600 tty5     00:00:00 mingetty
 2601 tty2     00:00:00 mingetty
 2602 tty3     00:00:00 mingetty
 2603 tty6     00:00:00 mingetty
 2637 tty7     00:02:58 X

The actual device to which a tty is connected is determined when it's opened by the kernel, and the "number" used is seldom related to any physical device. As you can see in the listing above, on this laptop tty7 is connected to the X-server and tty[2-6] are connected to terminal consoles.

Jinouchi · 01-14-2009, 03:28 PM

Well, I don't have any idea what your Linux knowledge level is, but the command

Code:

lsusb

will list all attached USB devices. Otherwise

Code:

fdisk -l

will give you a list of all attached filesystems.

Hope that helps...

Cottsay · 01-14-2009, 09:50 PM

A viable way to identify a device is to use the "dmesg" command, grepping the output to the device you're looking for. For example, if you have two video input cards, say /dev/video0 and /dev/video1, you could run:

dmesg | grep video0

and hopefully, you could find some information, such as the driver, that could help identify the device.

Good luck!

--scott