Linux logged out a user automatically

There are several possible reasons why a user might be logged out of a Linux system automatically. Some common reasons for this include the following:

• The user has reached the maximum idle time, which is the maximum amount of time that a user can remain logged in without any activity. By default, many Linux systems are configured to log out a user automatically after a certain amount of idle time, to prevent unauthorized access to the system. The maximum idle time can be configured using the TMOUT shell variable or the pam_umask module in the /etc/pam.d directory.
• The user has exceeded the maximum login time, which is the maximum amount of time that a user can remain logged in to the system. This limit can be set using the pam_umask module in the /etc/pam.d directory, or by using the ulimit command to set the maximum CPU time or maximum number of processes that a user can use.
• The user has exceeded the maximum number of sessions, which is the maximum number of concurrent sessions that a user is allowed to have. This limit can be set using the pam_umask module in the /etc/pam.d directory, or by using the ulimit command to set the maximum number of open files or maximum number of processes that a user can have.
• The user has reached the maximum password age, which is the maximum number of days that a user's password can remain unchanged before it expires. By default, many Linux systems are configured to force a user to change their password after a certain number of days, and to log out the user automatically if they do not change their password in time. This limit can be configured using the PASS_MAX_DAYS and PASS_MIN_DAYS settings in the /etc/login.defs file.

In general, if a user is logged out of a Linux system automatically, it is likely due to one of the above reasons or a similar configuration that limits the amount of time or resources that a user can use. To prevent this from happening, you can adjust the relevant settings and configuration options to allow the user to remain logged in for longer periods of time, or to increase the number of sessions or resources that they are allowed to use.