init(8) System Manager's Manual init(8)
Name
init - process control initialization
Syntax
/bin/init [ options ]
Description
The ULTRIX system invokes the command as the last step in the boot procedure. The system normally then runs the automatic reboot sequence,
as described in If succeeds, the command begins multiuser operation. If fails, begins single-user operation by giving the superuser a
shell on the console.
You can use the command so that parameters are passed from the boot program to so that multiuser operation begins immediately. When the
superuser terminates the single-user shell (by pressing CTRL/D), runs the command file without the reboot parameter. This command file
performs housekeeping operations such as removing temporary files, mounting file systems, and starting daemons. For further information,
see
In multiuser operation, creates a process for each terminal port where a user may log in. To begin such operations, it reads the file For
further information, see For each terminal that is marked ``on'' in the file, forks and invokes the command specified for the current line.
The command is passed the name of the terminal as the last argument. The other arguments (if any) are specified after the command in the
file. Usually, the command is but it may be any command.
The command reads the user's name and invokes to log in the user and execute the shell.
Ultimately, the shell terminates because of an end-of-file. The end-of-file may be typed explicitly or generated as a result of hanging up
on a terminal line. The main path of which has been waiting for such an event, wakes up and removes the appropriate entry from the file
which records current users. The command then makes an entry in which maintains a history of logins and logouts. The entry is made only
if a user logged in successfully on the line. Then the appropriate terminal is reopened and is reinvoked.
The command catches the signal (signal SIGHUP) and interprets it to mean that the file should be read again. The shell process on each
line which used to be active in but is no longer there is terminated; a new process is created for each added line; lines unchanged in the
file are undisturbed. Thus it is possible to drop or add phone lines without rebooting the system by changing the file and sending a sig-
nal to the process, using kill -HUP 1.
The command terminates multiuser operations and resumes single-user mode if it receives a terminate (TERM) signal. That is, the superuser
types kill -TERM 1. If there are processes outstanding which are deadlocked (due to hardware or software failure), does not wait for them
all to die, but times out after 30 seconds and prints a warning message.
If receives a terminal stop signal (the superuser types kill -TSTP 1), stops creating new processes and lets the system slowly die away. A
later hangup will resume full multiuser operations, or a terminate will initiate a single user shell. This feature is used by and
If dies, the system will reboot itself automatically. If, at bootstrap time, the process cannot be located, the system will loop in user
mode at location 0x13.
Options
-a Specifies that the system should autoreboot to multiuser mode. This option is similar to specifying to the console prompt or specify-
ing either with the -r option or from the command line.
-s Specifies that the system should boot to single-user mode.
Diagnostics
WARNING: Something is hung (wont die); ps axl advised
The system is shutting down and cannot kill a certain process. This usually occurs when a process cannot exit a device driver due to a
persistent device error condition.
init: `command tty' failing, sleeping.
The command tried to spawn a new process (use the system call) for the command five times. Each time, the command failed. This may indi-
cate that the command was invoked with invalid arguments. Check the file for errors. This error message is printed at level LOG_ERR.
init: exec failed: cmd= command reason
The command tried to spawn a new process using the system call for the command. The failed. The reason is the explanation produced by the
routine for why the failed. This error message is printed at level LOG_ERR.
Files
Lists current system users
History of logins and logouts
The command reads this file for a command to execute for the terminal line
Command file executed by
See Also
ttys(5), getty(8), rc(8), reboot(8)
RISC init(8)