cron runs shell commands from crontabs.
But having just got caught out by the differences between zsh and bash, I'm now concerned that I don't know which shell cron uses to interpret crontab commands? Obviously the simple case where the cron entry just points to a script file is handled by the #!/path/to/interpreter
on the first line, but what when you have something more complex in cron?
I looked in /etc/cron*
and can't see anything that might allow this to be set or changed?
man crontab
but notman 5 crontab
)