- If during an action, user does not exist ignore.
- If during an action, return a non-zero exist status.
- Catch an errors during actions as exceptions.
- Display a message that corresponding POSIX operation failed.
The package license (AGPL3+) implicitly indicates the license of each
file. However, it is desirable to have license headers in each file.
This is the case for many prominent projects like GNU project, Mozilla
etc.