osx man page for nologin

NOLOGIN(5)						      BSD File Formats Manual							NOLOGIN(5)

NAME
     nologin -- disallow logins

DESCRIPTION
     Programs such as login(1) disallow logins if the nologin file exists.  The programs display the contents of nologin to the user if possible
     and interrupt the login sequence.	This makes it simple to temporarily prevent incoming logins systemwide.

     To disable logins on a per-account basis, investigate nologin(8).

SECURITY
     The nologin file is ignored for user root by default.

IMPLEMENTATION NOTES
     The nologin feature is implemented through login.conf(5), which allows to change the pathname of the file and to extend the list of users
     exempt from temporary login restriction.

     PAM-aware programs can be selectively configured to respect nologin using the pam_nologin(8) module via pam.conf(5).

     The nologin file will be removed at system boot if it resides in /var/run and cleanvar_enable is set to ``YES'' in rc.conf(5), which is
     default.  Therefore system reboot can effectively re-enable logins.

FILES
     /var/run/nologin  default location of nologin

SEE ALSO
     login(1), login.conf(5), pam.conf(5), rc.conf(5), nologin(8), pam_nologin(8), shutdown(8)

BSD
								   May 10, 2007 							       BSD