Is the default shell to run %post section sh or bash on Ubuntu 22.04?

[Heng-Zhou]

The document of %post section says

Which then is the default shell to run %post section on Ubuntu 22.04?

[dtrudg]

/bin/sh is called by default. On many distributions this is a symlink to bash. However, on Ubuntu it is dash, which is a POSIX sh shell.

Generally, it is safest to write %post etc. assuming they will run on a POSIX sh compatible shell. If you need to use non-sh syntax, specify a custom shell with -c as documented - https://docs.sylabs.io/guides/latest/user-guide/definition_files.html#post

[Heng-Zhou]

Thanks for the reply.