The Linux shell is not needed for normal operation or administration.
The Linux shell level can be accessed as a root user from the console and via SSH. Use ALT+F2 to switch from the Intra2net system console to the Linux shell login.
Changes to the Linux shell can seriously affect the functionality, stability and security of the Intra2net system. It may not be immediately apparent that this is the case, but rather may only cause problems after a certain period of time, such as after an update.