Custom DNS support and better codes

[sayem314]

I have added support for custom DNS and improved overall coding. Also fixed a DNS(9) bug.

[angristan]

Hello, and thank you for your PR.

Could you please explain what does read -rp enhances? What about || return?

Also if it doesn't bother you, could you do 2 separate PRs? 🙏

[jellemdekker]

1. Could you please explain what does read -rp enhances?

From the bash manpage about the built-in read command:

-p prompt: output the string PROMPT without a trailing newline before
attempting to read
-r: do not allow backslashes to escape any characters

2. What about || return?

From shellcheck's wiki:

Rationale:
cd can fail for a variety of reasons: misspelled paths, missing directories, missing permissions, broken symlinks and more.

If/when it does, the script will keep going and do all its operations in the wrong directory. This can be messy, especially if the operations involve creating or deleting a lot of files.

To avoid this, make sure you handle the cases when cd fails. Ways to do this include

cd foo || exit as suggested to just abort immediately
if cd foo; then echo "Ok"; else echo "Fail"; fi for custom handling
<(cd foo && cmd) as an alternative to <(cd foo || exit; cmd) in <(..), $(..) or ( )

Except instead of cd foo || exit, it's now cd foo || return.

[jellemdekker]

@sayem314 Please split up your pull request so that the code for support for custom DNS is in a separate PR.

[sayem314]

I’m on vacation for Ramadan. Can’t really make pull request now. I have to update it after Eid. In the meantime if anyone would like to work on that I have no problem with that 🙂 And sorry about real late reply 😔

[sayem314]

Closing this in favor of new PR

[angristan]

But custom DNS is gone D:

[sayem314]

Oh yeah. Forgot about that. Also I broke my wrist 😔

Anyway I will make sure to pull request for custom DNS shortly.