clean up shell script

[gy741]

Fixes

Hello,

In my opinion, No GIT_VERSION variable are required.

And, Use of` "``" is not recommended.

Ref: http://mywiki.wooledge.org/BashFAQ/082
https://stackoverflow.com/questions/4708549/what-is-the-difference-between-command-and-command-in-shell-programming

What do you think of it?

Thanks.

Checklist

• I have made a material change to the repo (functionality, testing, spelling, grammar)
• I have read the [Contribution Guide] and my PR follows them.
• I updated my branch with the master branch.
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation about the functionality in the appropriate .md file
• I have added in line documentation to the code I modified

Short description of what this PR does:

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[thinkingserious]

Hello @gy741,

Thanks again for the PR!

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