refactor: lint shell for shellcheck

[zaunist]

Please answer these questions before submitting a pull request, or your PR will get closed.

Why submit this pull request?

• Bugfix
• New feature provided
• Improve performance
• Backport patches

What changes will this PR take into?

Refer to shellcheck to standardize shell scripting.
example:

pwd=`pwd`

to:

pwd=$(pwd)

Checklist:

• Did you explain what problem does this PR solve? Or what new features have been added?
• Have you added corresponding test cases?
• Have you modified the corresponding document?
• Is this PR backward compatible? If it is not backward compatible, please discuss on the mailing list first

[codecov-commenter]

Codecov Report

Merging #2193 (d936c95) into master (e1e83e3) will decrease coverage by 2.33%.
The diff coverage is n/a.

❗ Current head d936c95 differs from pull request most recent head e7c45b6. Consider uploading reports for the commit e7c45b6 to get more accurate results

@@            Coverage Diff             @@
##           master    #2193      +/-   ##
==========================================
- Coverage   69.45%   67.11%   -2.34%     
==========================================
  Files         189       62     -127     
  Lines        7281     3929    -3352     
  Branches      824        0     -824     
==========================================
- Hits         5057     2637    -2420     
+ Misses       1927      997     -930     
+ Partials      297      295       -2     

Flag	Coverage Δ
backend-e2e-test	?
backend-e2e-test-ginkgo	49.78% <ø> (+0.12%)	⬆️
backend-unit-test	50.39% <ø> (+0.03%)	⬆️
frontend-e2e-test	?

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
api/internal/handler/data_loader/route_import.go	32.11% <0.00%> (-35.41%)	⬇️
api/internal/handler/global_rule/global_rule.go	68.11% <0.00%> (-17.40%)	⬇️
api/internal/core/entity/entity.go	77.27% <0.00%> (-13.64%)	⬇️
api/internal/utils/utils.go	60.00% <0.00%> (-13.00%)	⬇️
api/internal/core/store/storehub.go	68.80% <0.00%> (-3.21%)	⬇️
api/internal/core/store/validate.go	68.68% <0.00%> (-2.03%)	⬇️
api/internal/handler/label/label.go	84.48% <0.00%> (-1.73%)	⬇️
api/internal/core/store/store.go	88.54% <0.00%> (-0.53%)	⬇️
...nents/Upstream/components/ServiceDiscoveryArgs.tsx
.../components/passive-check/Healthy/HttpStatuses.tsx
... and 125 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update e1e83e3...e7c45b6. Read the comment docs.

[zaunist]

cc @starsz @nic-6443 @bzp2010 @iamayushdas

[bzp2010]

@zaunist I think we can leave the changes to cli_test.sh here, it will cause a conflict with another PR [1] that actually refactors it.

[1] #2183

[zaunist]

@zaunist I think we can leave the changes to cli_test.sh here, it will cause a conflict with another PR [1] that actually refactors it.

[1] #2183

Yes, I have undone the changes to cli_test.sh

[zaunist]

cc @bzp2010