About the difference between a login shell and a non-logon shell

What is login Shell: Login shell can be used by user login, such as/bin/bash,/bin/sh,/bin/csh ... The general Linux Default User shell is bash, which means you can log in and write commands.

Non-logon shell: The classic/bin/nologin is a non-login shell, which means that if a user defaults to it, the user will not be able to use Linux even if they are logged into Linux.

The shell is the user and the computer communication medium, the login shell guarantees the user and the computer exchanges, the non login Shell cannot let the computer and the user communicate.

The default logon shell for the user is recorded in the/etc/passwd file.

Non-login Shell has his specific purpose, such as a Linux-built FTP server, and create more than one user, you can change the default shell of these users to nologin, so that these users, although they are Linux users can not log into the Linux host, Only access to the FTP server, which also ensures security!