fix bash not_found handler

[jdx]

Fixes #1557

Also refactored all the shell activate scripts

[codacy-production]

Coverage summary from Codacy

See diff coverage on Codacy

Coverage variation	Diff coverage
✅ -0.03%	✅ 88.71%

Coverage variation details

	Coverable lines	Covered lines	Coverage
Common ancestor commit (6a16dc0)	16299	13618	83.55%
Head commit (b06aef6)	16233 (-66)	13558 (-60)	83.52% (-0.03%)

Coverage variation is the difference between the coverage for the head and common ancestor commits of the pull request branch: <coverage of head commit> - <coverage of common ancestor commit>

Diff coverage details

	Coverable lines	Covered lines	Diff coverage
Pull request (#1558)	62	55	88.71%

Diff coverage is the percentage of lines that are covered by tests out of the coverable lines that the pull request added or modified: <covered lines added or modified>/<coverable lines added or modified> * 100%

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