What two issues can cause shell problems in Linux?

The issues that can lead to shell problems in Linux often stem from improperly configured environment variables and default shell settings. Environment variables in a shell session dictate certain aspects of the operating environment for processes. If these variables are not set correctly, it can lead to commands failing to execute properly, scripts not running as intended, or user configurations not applying.

Default shell settings define how the shell behaves, including settings related to history, prompt appearance, and command execution behavior. If these settings are misconfigured, they can hinder user experience and functionality, making it difficult to work efficiently in the shell.

Addressing these two areas can significantly improve shell reliability and usability, ensuring that users have a functional command-line interface. While permissions and kernel modules, memory issues, and network settings can affect the overall system performance or specific applications, they are less directly related to the operation and behavior of the shell itself compared to the environment variables and shell settings.