Linux

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Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).

Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.

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A Linux user's nightmare: the machine was wiped clean with one click (www.mikrobitti.fi)

submitted 8 months ago by [email protected] to c/[email protected]

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[–] [email protected] 18 points 8 months ago (2 children)

Is there not also a way to disallow empty variables in the script, I think it is set -u? Then you don't have to keep thinking "should I add a :? here because if empty it may lead to disaster" all the time. Might be even safer.

[–] [email protected] 27 points 8 months ago (1 children)

set -euo pipefail at the top of every script makes stuff a lot safer. Explanation here.

[–] [email protected] 8 points 8 months ago

Yep! I always do this too.

TL;DR: e aborts the whole script on a non-zero error. u aborts when using an undefined variable. -o pipefail aborts a piped compound command when one of the piped commands fail.

Any other way lies madness. Or erasing the whole filesystem apparently!

[–] [email protected] 7 points 8 months ago* (last edited 8 months ago)

Yes! But -u is for undefined variables. It won't stop a defined variable with an empty value. E.g foo="".

Also ? and :? have the advantage of telling you right then and there where the variable use is that it must be defined or not empty... having to trek back to (likely) the top of the script to check is easily forgotten.