Submission Format

• script or patch
• test data used
• commands executed
• exit codes
• short risk and recovery note

Tasks

Task 01: quoting

Build a small script or improve an existing example focused on quoting.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 02: exit codes

Build a small script or improve an existing example focused on exit codes.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 03: pipelines

Build a small script or improve an existing example focused on pipelines.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 04: getopts

Build a small script or improve an existing example focused on getopts.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 05: trap

Build a small script or improve an existing example focused on trap.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 06: mktemp

Build a small script or improve an existing example focused on mktemp.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 07: text processing

Build a small script or improve an existing example focused on text processing.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 08: security

Build a small script or improve an existing example focused on security.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 09: quoting

Build a small script or improve an existing example focused on quoting.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 10: exit codes

Build a small script or improve an existing example focused on exit codes.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 11: pipelines

Build a small script or improve an existing example focused on pipelines.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 12: getopts

Build a small script or improve an existing example focused on getopts.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 13: trap

Build a small script or improve an existing example focused on trap.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 14: mktemp

Build a small script or improve an existing example focused on mktemp.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 15: text processing

Build a small script or improve an existing example focused on text processing.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 16: security

Build a small script or improve an existing example focused on security.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 17: quoting

Build a small script or improve an existing example focused on quoting.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 18: exit codes

Build a small script or improve an existing example focused on exit codes.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 19: pipelines

Build a small script or improve an existing example focused on pipelines.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 20: getopts

Build a small script or improve an existing example focused on getopts.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 21: trap

Build a small script or improve an existing example focused on trap.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 22: mktemp

Build a small script or improve an existing example focused on mktemp.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 23: text processing

Build a small script or improve an existing example focused on text processing.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 24: security

Build a small script or improve an existing example focused on security.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 25: quoting

Build a small script or improve an existing example focused on quoting.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 26: exit codes

Build a small script or improve an existing example focused on exit codes.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 27: pipelines

Build a small script or improve an existing example focused on pipelines.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 28: getopts

Build a small script or improve an existing example focused on getopts.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 29: trap

Build a small script or improve an existing example focused on trap.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 30: mktemp

Build a small script or improve an existing example focused on mktemp.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 31: text processing

Build a small script or improve an existing example focused on text processing.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 32: security

Build a small script or improve an existing example focused on security.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 33: quoting

Build a small script or improve an existing example focused on quoting.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 34: exit codes

Build a small script or improve an existing example focused on exit codes.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 35: pipelines

Build a small script or improve an existing example focused on pipelines.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Task 36: getopts

Build a small script or improve an existing example focused on getopts.

Requirements:

• bash -n must pass.
• Invalid inputs must return an explainable exit code.
• Human and machine output must be separated.
• The script must not use production paths or secrets.

Evidence:

bash -n script.sh
./script.sh --help
./script.sh --dry-run
echo "$?"

Solution Notes

Use small functions, consistent quoting and a clear usage function. Write down the error path first and then the happy path. Dry-run is mandatory for destructive operations.

Review Checklist for Exercises Intermediate

• 01. name the shebang and target shell explicitly: Record the affected file, command, exit code and risk.
• 02. quote variable expansions unless word splitting is deliberate: Record the affected file, command, exit code and risk.
• 03. validate inputs before they influence filenames, options or commands: Record the affected file, command, exit code and risk.
• 04. evaluate and document exit codes explicitly: Record the affected file, command, exit code and risk.
• 05. separate stderr and stdout: Record the affected file, command, exit code and risk.
• 06. create temporary files with mktemp: Record the affected file, command, exit code and risk.
• 07. test cleanup through trap: Record the affected file, command, exit code and risk.
• 08. guard destructive operations with dry-run, scope checks and confirmation: Record the affected file, command, exit code and risk.
• 09. never print or commit secrets: Record the affected file, command, exit code and risk.
• 10. check PATH and external dependencies: Record the affected file, command, exit code and risk.
• 11. handle ShellCheck warnings or suppress them with a reason: Record the affected file, command, exit code and risk.
• 12. document portability assumptions between Bash and POSIX sh: Record the affected file, command, exit code and risk.
• 13. name the shebang and target shell explicitly: Record the affected file, command, exit code and risk.
• 14. quote variable expansions unless word splitting is deliberate: Record the affected file, command, exit code and risk.
• 15. validate inputs before they influence filenames, options or commands: Record the affected file, command, exit code and risk.
• 16. evaluate and document exit codes explicitly: Record the affected file, command, exit code and risk.
• 17. separate stderr and stdout: Record the affected file, command, exit code and risk.
• 18. create temporary files with mktemp: Record the affected file, command, exit code and risk.
• 19. test cleanup through trap: Record the affected file, command, exit code and risk.
• 20. guard destructive operations with dry-run, scope checks and confirmation: Record the affected file, command, exit code and risk.
• 21. never print or commit secrets: Record the affected file, command, exit code and risk.
• 22. check PATH and external dependencies: Record the affected file, command, exit code and risk.
• 23. handle ShellCheck warnings or suppress them with a reason: Record the affected file, command, exit code and risk.
• 24. document portability assumptions between Bash and POSIX sh: Record the affected file, command, exit code and risk.
• 25. name the shebang and target shell explicitly: Record the affected file, command, exit code and risk.
• 26. quote variable expansions unless word splitting is deliberate: Record the affected file, command, exit code and risk.
• 27. validate inputs before they influence filenames, options or commands: Record the affected file, command, exit code and risk.
• 28. evaluate and document exit codes explicitly: Record the affected file, command, exit code and risk.
• 29. separate stderr and stdout: Record the affected file, command, exit code and risk.
• 30. create temporary files with mktemp: Record the affected file, command, exit code and risk.
• 31. test cleanup through trap: Record the affected file, command, exit code and risk.
• 32. guard destructive operations with dry-run, scope checks and confirmation: Record the affected file, command, exit code and risk.
• 33. never print or commit secrets: Record the affected file, command, exit code and risk.
• 34. check PATH and external dependencies: Record the affected file, command, exit code and risk.
• 35. handle ShellCheck warnings or suppress them with a reason: Record the affected file, command, exit code and risk.
• 36. document portability assumptions between Bash and POSIX sh: Record the affected file, command, exit code and risk.
• 37. name the shebang and target shell explicitly: Record the affected file, command, exit code and risk.
• 38. quote variable expansions unless word splitting is deliberate: Record the affected file, command, exit code and risk.
• 39. validate inputs before they influence filenames, options or commands: Record the affected file, command, exit code and risk.
• 40. evaluate and document exit codes explicitly: Record the affected file, command, exit code and risk.
• 41. separate stderr and stdout: Record the affected file, command, exit code and risk.
• 42. create temporary files with mktemp: Record the affected file, command, exit code and risk.
• 43. test cleanup through trap: Record the affected file, command, exit code and risk.
• 44. guard destructive operations with dry-run, scope checks and confirmation: Record the affected file, command, exit code and risk.
• 45. never print or commit secrets: Record the affected file, command, exit code and risk.
• 46. check PATH and external dependencies: Record the affected file, command, exit code and risk.
• 47. handle ShellCheck warnings or suppress them with a reason: Record the affected file, command, exit code and risk.
• 48. document portability assumptions between Bash and POSIX sh: Record the affected file, command, exit code and risk.
• 49. name the shebang and target shell explicitly: Record the affected file, command, exit code and risk.
• 50. quote variable expansions unless word splitting is deliberate: Record the affected file, command, exit code and risk.

Practice Appendix: Exercises Intermediate

This appendix is a working backlog for longer trainings, reviews and repetitions. Each task can be checked locally with Bash, test data and a Git repository.

A001. quoting

• Task: validate input and connect the observation explicitly to quoting.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A002. exit codes

• Task: explain exit code and connect the observation explicitly to exit codes.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A003. pipelines

• Task: check quoting and connect the observation explicitly to pipelines.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A004. getopts

• Task: test error path and connect the observation explicitly to getopts.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A005. trap

• Task: review log output and connect the observation explicitly to trap.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A006. mktemp

• Task: trace cleanup and connect the observation explicitly to mktemp.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A007. text processing

• Task: scope portability and connect the observation explicitly to text processing.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A008. security

• Task: mark security risk and connect the observation explicitly to security.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A009. quoting

• Task: document recovery path and connect the observation explicitly to quoting.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A010. exit codes

• Task: write review rule and connect the observation explicitly to exit codes.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A011. pipelines

• Task: validate input and connect the observation explicitly to pipelines.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A012. getopts

• Task: explain exit code and connect the observation explicitly to getopts.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A013. trap

• Task: check quoting and connect the observation explicitly to trap.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A014. mktemp

• Task: test error path and connect the observation explicitly to mktemp.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A015. text processing

• Task: review log output and connect the observation explicitly to text processing.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A016. security

• Task: trace cleanup and connect the observation explicitly to security.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A017. quoting

• Task: scope portability and connect the observation explicitly to quoting.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A018. exit codes

• Task: mark security risk and connect the observation explicitly to exit codes.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A019. pipelines

• Task: document recovery path and connect the observation explicitly to pipelines.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A020. getopts

• Task: write review rule and connect the observation explicitly to getopts.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A021. trap

• Task: validate input and connect the observation explicitly to trap.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A022. mktemp

• Task: explain exit code and connect the observation explicitly to mktemp.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A023. text processing

• Task: check quoting and connect the observation explicitly to text processing.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A024. security

• Task: test error path and connect the observation explicitly to security.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A025. quoting

• Task: review log output and connect the observation explicitly to quoting.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A026. exit codes

• Task: trace cleanup and connect the observation explicitly to exit codes.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A027. pipelines

• Task: scope portability and connect the observation explicitly to pipelines.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A028. getopts

• Task: mark security risk and connect the observation explicitly to getopts.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A029. trap

• Task: document recovery path and connect the observation explicitly to trap.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A030. mktemp

• Task: write review rule and connect the observation explicitly to mktemp.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A031. text processing

• Task: validate input and connect the observation explicitly to text processing.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A032. security

• Task: explain exit code and connect the observation explicitly to security.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A033. quoting

• Task: check quoting and connect the observation explicitly to quoting.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A034. exit codes

• Task: test error path and connect the observation explicitly to exit codes.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A035. pipelines

• Task: review log output and connect the observation explicitly to pipelines.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A036. getopts

• Task: trace cleanup and connect the observation explicitly to getopts.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A037. trap

• Task: scope portability and connect the observation explicitly to trap.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A038. mktemp

• Task: mark security risk and connect the observation explicitly to mktemp.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A039. text processing

• Task: document recovery path and connect the observation explicitly to text processing.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A040. security

• Task: write review rule and connect the observation explicitly to security.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A041. quoting

• Task: validate input and connect the observation explicitly to quoting.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A042. exit codes

• Task: explain exit code and connect the observation explicitly to exit codes.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A043. pipelines

• Task: check quoting and connect the observation explicitly to pipelines.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A044. getopts

• Task: test error path and connect the observation explicitly to getopts.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A045. trap

• Task: review log output and connect the observation explicitly to trap.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A046. mktemp

• Task: trace cleanup and connect the observation explicitly to mktemp.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A047. text processing

• Task: scope portability and connect the observation explicitly to text processing.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A048. security

• Task: mark security risk and connect the observation explicitly to security.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A049. quoting

• Task: document recovery path and connect the observation explicitly to quoting.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A050. exit codes

• Task: write review rule and connect the observation explicitly to exit codes.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A051. pipelines

• Task: validate input and connect the observation explicitly to pipelines.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A052. getopts

• Task: explain exit code and connect the observation explicitly to getopts.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A053. trap

• Task: check quoting and connect the observation explicitly to trap.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A054. mktemp

• Task: test error path and connect the observation explicitly to mktemp.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A055. text processing

• Task: review log output and connect the observation explicitly to text processing.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A056. security

• Task: trace cleanup and connect the observation explicitly to security.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A057. quoting

• Task: scope portability and connect the observation explicitly to quoting.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A058. exit codes

• Task: mark security risk and connect the observation explicitly to exit codes.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A059. pipelines

• Task: document recovery path and connect the observation explicitly to pipelines.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A060. getopts

• Task: write review rule and connect the observation explicitly to getopts.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A061. trap

• Task: validate input and connect the observation explicitly to trap.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A062. mktemp

• Task: explain exit code and connect the observation explicitly to mktemp.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A063. text processing

• Task: check quoting and connect the observation explicitly to text processing.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A064. security

• Task: test error path and connect the observation explicitly to security.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A065. quoting

• Task: review log output and connect the observation explicitly to quoting.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A066. exit codes

• Task: trace cleanup and connect the observation explicitly to exit codes.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A067. pipelines

• Task: scope portability and connect the observation explicitly to pipelines.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A068. getopts

• Task: mark security risk and connect the observation explicitly to getopts.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A069. trap

• Task: document recovery path and connect the observation explicitly to trap.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A070. mktemp

• Task: write review rule and connect the observation explicitly to mktemp.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A071. text processing

• Task: validate input and connect the observation explicitly to text processing.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A072. security

• Task: explain exit code and connect the observation explicitly to security.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A073. quoting

• Task: check quoting and connect the observation explicitly to quoting.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A074. exit codes

• Task: test error path and connect the observation explicitly to exit codes.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A075. pipelines

• Task: review log output and connect the observation explicitly to pipelines.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A076. getopts

• Task: trace cleanup and connect the observation explicitly to getopts.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A077. trap

• Task: scope portability and connect the observation explicitly to trap.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A078. mktemp

• Task: mark security risk and connect the observation explicitly to mktemp.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A079. text processing

• Task: document recovery path and connect the observation explicitly to text processing.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A080. security

• Task: write review rule and connect the observation explicitly to security.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A081. quoting

• Task: validate input and connect the observation explicitly to quoting.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A082. exit codes

• Task: explain exit code and connect the observation explicitly to exit codes.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A083. pipelines

• Task: check quoting and connect the observation explicitly to pipelines.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A084. getopts

• Task: test error path and connect the observation explicitly to getopts.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A085. trap

• Task: review log output and connect the observation explicitly to trap.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A086. mktemp

• Task: trace cleanup and connect the observation explicitly to mktemp.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A087. text processing

• Task: scope portability and connect the observation explicitly to text processing.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A088. security

• Task: mark security risk and connect the observation explicitly to security.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A089. quoting

• Task: document recovery path and connect the observation explicitly to quoting.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.

A090. exit codes

• Task: write review rule and connect the observation explicitly to exit codes.
• Evidence: Record the checked command, expected output, actual output and exit code.
• Operations question: What happens with empty input, missing files, missing tools and repeated execution?
• Security question: Can input become an option, path, glob, subshell, eval expression or secret leak?
• Recovery: Describe revert, cleanup, restore, secret rotation or manual correction.