nohup(1)							   User Commands							  nohup(1)

NAME

       nohup - run a command immune to hangups

SYNOPSIS

       /usr/bin/nohup command [argument]...

       /usr/bin/nohup -p [-Fa] pid [pid]...

       /usr/bin/nohup -g [-Fa] gpid [gpid]...

       /usr/xpg4/bin/nohup command [argument]...

DESCRIPTION

       The nohup utility invokes the named command with the arguments supplied.  When the command is invoked, nohup arranges for the SIGHUP signal
       to be ignored by the process.

       When invoked with the -p or -g flags, nohup arranges for processes already running as identified by a list of process  IDs  or  a  list	of
       process group IDs to become immune to hangups.

       The  nohup utility can be used when it is known that command takes a long time to run and the user wants to log out of the terminal. When a
       shell exits, the system sends its children SIGHUP signals, which by default cause them to be killed. All stopped, running,  and	background
       jobs  ignores SIGHUP and continue running, if their invocation is preceded by the nohup command or if the process programmatically has cho-
       sen to ignore SIGHUP.

       /usr/bin/nohup		  Processes run by /usr/bin/nohup are immune to SIGHUP (hangup) and SIGQUIT (quit) signals.

       /usr/bin/nohup -p [-Fa]	  Processes specified by ID are made immune to SIGHUP and SIGQUIT, and all output to the controlling  terminal	is
				  redirected  to  nohup.out.  If  -F is specified, nohup forces control of each process. If -a is specified, nohup
				  changes the signal disposition of SIGHUP and SIGQUIT even if the process has installed a handler for either sig-
				  nal.

       /usr/bin/nohup -g [-Fa]	  Every  process in the same process group as the processes specified by ID are made immune to SIGHUP and SIGQUIT,
				  and all output to the controlling terminal is redirected to nohup.out. If -F is specified, nohup forces  control
				  of  each  process.  If  -a  is specified, nohup changes the signal disposition of SIGHUP and SIGQUIT even if the
				  process has installed a handler for either signal.

       /usr/xpg4/bin/nohup	  Processes run by /usr/xpg4/bin/nohup are immune to SIGHUP.

				  The nohup utility does not arrange to make processes immune to a SIGTERM  (terminate)  signal,  so  unless  they
				  arrange to be immune to SIGTERM or the shell makes them immune to SIGTERM, they will receive it.

				  If  nohup.out  is  not  writable in the current directory, output is redirected to $HOME/nohup.out. If a file is
				  created, the file has read and write permission (600. See chmod(1). If the standard error is a terminal,  it	is
				  redirected  to  the standard output, otherwise it is not redirected. The priority of the process run by nohup is
				  not altered.

OPTIONS

       The following options are supported:

       -a    Always changes the signal disposition of target processes. This option is valid only when specified with -p or -g.

       -F    Force. Grabs the target processes even if another process has control. This option is valid only when specified with -p or -g.

       -g    Operates on a list of process groups. This option is not valid with -p.

       -p    Operates on a list of processes. This option is not valid with -g.

OPERANDS

       The following operands are supported:

       pid	   A decimal process ID to be manipulated by nohup -p.

       pgid	   A decimal process group ID to be manipulated by nohup -g.

       command	   The name of a command that is to be invoked. If the command operand names any of the special shell_builtins(1)  utilities,  the
		   results are undefined.

       argument    Any string to be supplied as an argument when invoking the command operand.

USAGE

       Caution	should	be exercised when using the -F flag. Imposing two controlling processes on one victim process can lead to chaos. Safety is
       assured only if the primary controlling process, typically a debugger, has stopped the victim process and the primary  controlling  process
       is doing nothing at the moment of application of the proc tool in question.

EXAMPLES

       Example 1 Applying nohup to pipelines or command lists

       It  is  frequently desirable to apply nohup to pipelines or lists of commands. This can be done only by placing pipelines and command lists
       in a single file, called a shell script. One can then issue:

	 example$ nohup sh file

       and the nohup applies to everything in file. If the shell script file is to be executed often, then the need to type sh can  be	eliminated
       by giving file execute permission.

       Add an ampersand and the contents of file are run in the background with interrupts also ignored (see sh(1)):

	 example$ nohup file &

       Example 2 Applying nohup -p to a process

	 example$ long_running_command &
	 example$ nohup -p `pgrep long_running_command`

       Example 3 Applying nohup -g to a process group

	 example$ make &
	 example$ ps -o sid -p $$
	    SID
	 81079
	 example$ nohup -g `pgrep -s 81079 make`

ENVIRONMENT VARIABLES

       See  environ(5) for descriptions of the following environment variables that affect the execution of nohup: LANG, LC_ALL, LC_CTYPE, LC_MES-
       SAGES, PATH, NLSPATH, and PATH.

       HOME    Determine the path name of the user's home directory: if the output file nohup.out cannot be created in the current directory,  the
	       nohup command uses the directory named by HOME to create the file.

EXIT STATUS

       The following exit values are returned:

       126    command was found but could not be invoked.

       127    An error occurred in nohup, or command could not be found

       Otherwise, the exit values of nohup are those of the command operand.

FILES

       nohup.out	  The output file of the nohup execution if standard output is a terminal and if the current directory is writable.

       $HOME/nohup.out	  The output file of the nohup execution if standard output is a terminal and if the current directory is not writable.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

   /usr/bin/nohup
       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+
       |CSI			     |Enabled			   |
       +-----------------------------+-----------------------------+

   /usr/xpg4/bin/nohup
       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWxcu4			   |
       +-----------------------------+-----------------------------+
       |CSI			     |Enabled			   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       batch(1),  chmod(1), csh(1), ksh(1), nice(1), pgrep(1), proc(1), ps(1), sh(1), shell_builtins(1), signal(3C), proc(4), attributes(5), envi-
       ron(5), standards(5)

WARNINGS

       If you are running the Korn shell (ksh(1)) as your login shell, and have nohup'ed jobs running when you attempt to log out, you are  warned
       with the message:

	 You have jobs running.

       You need to log out a second time to actually log out. However, your background jobs continues to run.

NOTES

       The  C-shell  (csh(1)) has a built-in command nohup that provides immunity from SIGHUP, but does not redirect output to nohup.out. Commands
       executed with `&' are automatically immune to HUP signals while in the background.

       nohup does not recognize command sequences. In the case of the following command,

	 example$ nohup command1; command2

       the nohup utility applies only to command1. The command,

	 example$ nohup (command1; command2)

       is syntactically incorrect.

SunOS 5.11							    19 Jun 2006 							  nohup(1)