secons Utility Manage Concurrent Login Options

The secons utility manages concurrent login options. You can configure  to prevent a user from logging in more than once. This prevents intruders from logging into the accounts of users who are already logged in.
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The secons utility manages concurrent login options. You can configure 
PAM Server Control
to prevent a user from logging in more than once. This prevents intruders from logging into the accounts of users who are already logged in.
This command has the following format:
secons [-d+] [-d-] [-ds] [-l+] [-l-] [-ls] \
[-u+ userName] [-u- userName] [-us userName]
  • -d+
    Enables concurrent logins for the user running the command.
  • -d-
    Disables concurrent logins for the user running the command. Using this command kills any concurrent logins of the user to the local computer.
    You can also place this command in the .login or .cshrc file of a user to disable concurrent logins.
  • -ds
    Displays the concurrent logins setting for the user running the command.
  • -l+
    Enables concurrent logins system-wide.
    By default, 
    PAM Server Control
    enables login, but in cases where the system is shut down for maintenance, you can disable login for a specific period.
  • -l-
    Disables concurrent logins system-wide.
  • -ls
    Displays system-wide login status.
  • -u+
    userName
    Enables concurrent logins for the defined user.
  • -u-
    userName
    Disables concurrent logins for the defined user.
  • -us
    userName
    Displays the concurrent logins setting for the defined user.