Display only specific text in bash output

Question

I am making a system info script which will output what version of CentOS a machine is running.

Currently, I have the following:

#!/bin/bash
distro=$(cat /etc/redhat-release)

echo "OS Version: $distro"

For the output, I get the following:

OS Version: CentOS Linux release 7.9.2009 (Core)

I would like to know how I can remove the (Core) section of the output.

Can you use uname? Otherwise you can use sed to remove some part of the string. — pfnuesel
– pfnuesel, Commented Jul 23, 2024 at 11:04
Hello @pfnuesel, Unfortunately uname doesn't give me the Linux Distro info. I am reading up on the sed command, but still trying to figure out how to use it. — hymcode
– hymcode, Commented Jul 23, 2024 at 11:17

terdon · Accepted Answer · 2024-07-23 12:05:10Z

1

Using the sed command in the following manner seems to have done what I need:

sed 's/[(].*//' /etc/redhat-release

Output:

CentOS Linux release 7.9.2009

Explanation:

s/old/new/ is the substitution operator and will replace old with new.
[(].* the [ ] denote a character class. Here, we have a character class of one character, (. The .* means "0 or more characters".
//: here we are leaving the right hand side of the substitution operator empty.

So with the above command, I am replacing everything from the first bracket ( until the end of the line with nothing, effectively deleting it.

terdon♦

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answered Jul 23, 2024 at 11:31

hymcode

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