fixed the broken unit tests

[arodage]

Merge Checklist

All boxes should be checked before merging the PR

• The changes in the PR have been built and tested
• [] Ready to merge

Description

• Removed hardcoded commandMap with absolute paths
• Implemented PATH-based command resolution using shell's built-in command lookup
• Added dynamic shell detection (bash → /bin/sh fallback)
• Updated test to match new behavior (expects echo hello instead of /usr/bin/echo hello)

Any Newly Introduced Dependencies

How Has This Been Tested?

[feiyu11859661]

Why remove the cmd map?

[arodage]

@feiyu11859661 Closing this PR. I will let you take care of it. We might need some mock implementation if we really need a code coverage.