claude-code - 💡(How to fix) Fix Claude used /bin/sh in cron for bash-syntax script — VNM Visual scraper silently broken for days [1 comments, 2 participants]

This is a trivially preventable error. Using bash -c '...' explicitly in the crontab entry is the correct approach. Claude knew the script used bash syntax. It should have written the cron with bash -c.

TL;DR

To prevent silent failures in cron jobs, use bash -c '...' explicitly when writing cron entries for scripts that contain bash-specific syntax.

Guidance

• Verify the shell used by the cron daemon to ensure it supports the syntax used in the script.
• Update the cron entry to use bash -c '...' to explicitly specify the shell, preventing reliance on the default /bin/sh.
• Review existing cron jobs to identify any other scripts that may be using bash-specific syntax without explicit shell specification.
• Consider adding logging or alerting mechanisms to detect and report silent failures in the future.

Example

# Incorrect cron entry
*/3 * * * * /path/to/script.sh

# Corrected cron entry
*/3 * * * * bash -c '/path/to/script.sh'

Notes

This solution assumes that the script is intended to be run with bash and that the cron daemon supports the use of bash -c. It's also important to note that this fix only addresses the specific issue described and may not prevent other types of silent failures.

Recommendation

Apply workaround: Use bash -c '...' explicitly in cron entries for scripts with bash-specific syntax to prevent silent failures. This approach ensures that the correct shell is used, even if the default shell is not bash.