[Explain] Ignore blank lines as crowdsec will anyways

[LaurenceJJones]

Fix #2610

Add check on stdin for zero length lines.

Expand line checker on files to ignore zero length lines.

Return error if tmp file or target file has no content.

Edit:

Add defer function to cleanup as if we returned early the temporary files were kept.

[github-actions]

@LaurenceJJones: There are no 'kind' label on this PR. You need a 'kind' label to generate the release automatically.

• /kind feature
• /kind enhancement
• /kind fix
• /kind chore
• /kind dependencies

Details

I am a bot created to help the crowdsecurity developers manage community feedback and contributions. You can check out my manifest file to understand my behavior and what I can do. If you want to use this for your project, you can check out the BirthdayResearch/oss-governance-bot repository.

[github-actions]

@LaurenceJJones: There are no area labels on this PR. You can add as many areas as you see fit.

• /area agent
• /area local-api
• /area cscli
• /area security
• /area configuration

Details

I am a bot created to help the crowdsecurity developers manage community feedback and contributions. You can check out my manifest file to understand my behavior and what I can do. If you want to use this for your project, you can check out the BirthdayResearch/oss-governance-bot repository.

[LaurenceJJones]

/kind enhancement
/area cscli

[codecov]

Codecov Report

Attention: 37 lines in your changes are missing coverage. Please review.

Comparison is base (7e5ab34) 58.22% compared to head (afb18b3) 58.18%.

Files	Patch %	Lines
cmd/crowdsec-cli/explain.go	35.08%	28 Missing and 9 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2630      +/-   ##
==========================================
- Coverage   58.22%   58.18%   -0.05%     
==========================================
  Files         201      201              
  Lines       27048    27077      +29     
==========================================
+ Hits        15750    15754       +4     
- Misses       9753     9772      +19     
- Partials     1545     1551       +6     

Flag	Coverage Δ
bats	38.35% <35.08%> (-0.05%)	⬇️
unit-linux	55.24% <ø> (+0.01%)	⬆️
unit-windows	51.56% <ø> (ø)

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