Using Grep/Awk/Sed to get a substring from a command

johnjust · 01-12-2010, 07:19 PM

Hello all, I'm looking for a way to get a substring from the command to identify my NVIDIA Driver Version. I'll be using this in Conky, in case anyone is interested...

The command to identify the driver version is:

Code:

cat /proc/driver/nvidia/version

It returns:

Code:

NVRM version: NVIDIA UNIX x86 Kernel Module  190.53  Tue Dec  8 18:51:41 PST 2009
GCC version:  gcc version 4.4.1 (Ubuntu 4.4.1-4ubuntu8)

I'd like to just grab the "190.53" part of that. There are 2 spaces before and after it - the first 2 occurrences of double spaces, which I figure could be used with a substring command (if there's a better or easier way to do it, please let me know, this is just the solution that jumped out at me).

I know I could get it with some trial and error (maybe a couple of days, if I'm lucky, lol), but can anyone out there get it quicker? I checked out a couple forum posts on the subject, but I'm just getting a lot of errors when I try to adapt the code to fit my needs.

Thanks for any help!

syg00 · 01-12-2010, 07:38 PM

If it's always in the same field, awk

Code:

awk '/NVIDIA/ {print $8}'

If there is the possibility the text could change, parse for it

Code:

sed -nr '/NVIDIA/ s/.*([[:digit:]]*\.[[:digit:]]*).*/\1/p'

(all untested)

johnjust · 01-12-2010, 07:44 PM

Wow, I wasn't even close... I guess taking other people's examples and trying to change them doesn't always work.

In any case, AWK worked perfectly!

SED only returned ".53"

I assume it's always in the same spot, so I'll stick with the AWK command for now. I'll also have to devote some time to decipher those commands so I actually learn something...

Thanks a bunch! In case anyone wants to use it, here is the full command:

Code:

cat /proc/driver/nvidia/version | awk '/NVIDIA/ {print $8}'

And, in Conky:

Code:

${exec cat /proc/driver/nvidia/version | awk '/NVIDIA/ {print $8}'}

GrapefruiTgirl · 01-12-2010, 07:51 PM

Quote:

Originally Posted by johnjust

Wow, I wasn't even close... I guess taking other people's examples and trying to change them doesn't always work.

Correct, it doesn't always work exactly as you want (and sometimes not at all) but it DOES teach you something (whether it works or not, you still learn from it). And taking such commands and playing with them in a console, making small adjustments and re-trying it over and over, can learn you a lot more than just taking a command, finding it works, and using it and forgetting about it.

Cheers!
Sasha

PS - I see you added that line for conky. I'm not familiar with conky, but are you sure you need that "exec" in there? (maybe you do, I'm just asking..)

johnjust · 01-12-2010, 07:55 PM

Ha, I also added a line in there saying I should learn something from it, which I fully intend to do. My first guess on the AWK command is the "$8" being the 8th "word" in the output, which could be why it would only work if it always appears in the same place. I'm not sure what the "/NVIDIA/" part does - maybe to identify the line?

As far as I know, "exec" is used to execute a shell command inside Conky, although I'm new to that as well.

syg00 · 01-12-2010, 08:02 PM

My bad - told you it was untested ...

Hint - the regex needs to be stricter; adding a class for white-space in the appropriate spot will do it.