Diffrernce between cat and zcat

ZAMO · 06-27-2007, 02:57 AM

Hi,
Can anyone explain me the difference between "cat" and "zcat " command.
Thanks

jschiwal · 06-27-2007, 03:00 AM

Zcat is used to cat compressed files. For example, try "zcat /proc/config.gz | grep RAID"

b0uncer · 06-27-2007, 03:00 AM

zcat can take in compressed data, cat uses non-compressed, that's the difference I think.

ZAMO · 06-27-2007, 03:08 AM

Thank you for your replies

bartonski · 06-27-2007, 08:15 PM

Quote:

Originally Posted by jschiwal

Zcat is used to cat compressed files. For example, try "zcat /proc/config.gz | grep RAID"

Hmm. That file doesn't exist on my FC4 box. What distro are you using, and what does that file contain? (I understand what the /proc file system is, but I've never run into config.gz)

DeuceNegative · 06-27-2007, 10:31 PM

It contains the running kernel's configuration, just like /usr/src/linux/.config contains the configuration for the kernel that you compile. It might even be exactly that file, gzipped.

In order to have it available, it must be enabled when you configure the kernel (along with procfs, too):

Code:

General setup  --->
[*] Kernel .config support
[*]   Enable access to .config through /proc/config.gz

It corresponds to CONFIG_IKCONFIG_PROC. So if it's working, you could do

Code:

zcat /proc/config.gz | grep CONFIG_IKCONFIG_PROC

and see

Code:

CONFIG_IKCONFIG_PROC=y

(self-referentiality is fun)