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OpenSolaris 2009.06 - man page for wait (opensolaris section 1)

wait(1) 				  User Commands 				  wait(1)

NAME
       wait - await process completion

SYNOPSIS
   /bin/sh
       wait [pid]...

   /bin/jsh /bin/ksh /usr/xpg4/bin/sh
       wait [pid]...

       wait [% jobid...]

   /bin/csh
       wait

   ksh93
       wait [job...]

DESCRIPTION
       The  shell itself executes wait, without creating a new process. If you get the error mes-
       sage cannot fork,too many processes, try using the wait command to  clean  up  your  back-
       ground  processes.  If this doesn't help, the system process table is probably full or you
       have too many active foreground processes. There is a limit to the number of  process  IDs
       associated with your login, and to the number the system can keep track of.

       Not  all  the processes of a pipeline with three or more stages are children of the shell,
       and thus cannot be waited for.

   /bin/sh, /bin/jsh
       Wait for your background process whose process ID is pid and report its	termination  sta-
       tus.  If pid is omitted, all your shell's currently active background processes are waited
       for and the return code is 0. The wait utility accepts a job identifier, when Job  Control
       is enabled (jsh), and the argument, jobid, is preceded by a percent sign (%).

       If  pid	is  not an active process ID, the wait utility returns immediately and the return
       code is 0.

   csh
       Wait for your background processes.

   ksh
       When an asynchronous list is started by the shell, the process ID of the last  command  in
       each  element  of the asynchronous list becomes known in the current shell execution envi-
       ronment.

       If the wait utility is invoked with no operands, it waits until all process IDs	known  to
       the invoking shell have terminated and exit with an exit status of 0.

       If  one	or  more pid or jobid operands are specified that represent known process IDs (or
       jobids), the wait utility waits until all of them have terminated. If one or more  pid  or
       jobid  operands	are specified that represent unknown process IDs (or jobids), wait treats
       them as if they were known process IDs (or jobids) that exited with exit status	127.  The
       exit  status  returned  by the wait utility is the exit status of the process requested by
       the last pid or jobid operand.

       The known process IDs are applicable only for invocations of wait  in  the  current  shell
       execution environment.

   ksh93
       wait  with  no operands, waits until all jobs known to the invoking shell have terminated.
       If one or more job operands are specified, wait waits until all of  them  have  completed.
       Each job can be specified as one of the following:

       number	   number refers to a process ID.

       -number	   number refers to a process group ID.

       %number	   number refers to a job number

       %string	   Refers to a job whose name begins with string

       %?string    Refers to a job whose name contains string

       %+	   Refers to the current job
       %%

       %-	   Refers to the previous job

       If  one ore more job operands is a process id or process group id not known by the current
       shell environment, wait treats each of them as if it were a process that exited with  sta-
       tus 127.

OPERANDS
       The following operands are supported:

       pid	The unsigned decimal integer process ID of a command, for which the utility is to
		wait for the termination.

       jobid	A job control job ID that identifies a background process group to be waited for.
		The job control job ID notation is applicable only for invocations of wait in the
		current shell execution environment, and only on systems supporting the job  con-
		trol option.

USAGE
       On  most implementations, wait is a shell built-in. If it is called in a subshell or sepa-
       rate utility execution environment, such as one of the following,

	 (wait)
	 nohup wait ...
	 find . -exec wait ... \;

       it returns immediately because there is no known process IDs to wait for in those environ-
       ments.

EXAMPLES
       Example 1 Using A Script To Identify The Termination Signal

       Although  the exact value used when a process is terminated by a signal is unspecified, if
       it is known that a signal terminated a process, a script can  still  reliably  figure  out
       which signal is using kill, as shown by the following (/bin/ksh and /usr/xpg4/bin/sh):

	 sleep 1000&
	 pid=$!
	 kill -kill $pid
	 wait $pid
	 echo $pid was terminated by a SIG$(kill -l $(($?-128))) signal.

       Example 2 Returning The Exit Status Of A Process

       If  the	following  sequence  of  commands  is  run  in less than 31 seconds (/bin/ksh and
       /usr/xpg4/bin/sh):

	 sleep 257 | sleep 31 &

	 jobs -l %%

       then either of the following commands returns the exit status of the second sleep  in  the
       pipeline:

	 wait <pid of sleep 31>
	 wait %%

ENVIRONMENT VARIABLES
       See  environ(5)	for  descriptions  of the following environment variables that affect the
       execution of wait: LANG, LC_ALL, LC_CTYPE, LC_MESSAGES, and NLSPATH.

EXIT STATUS
   ksh93
       The following exit values are returned by the wait built-in in ksh93:

       0      wait was invoked with no operands. All processes known by the invoking process have
	      terminated.

       127    job  is a process id or process group id that is unknown to the current shell envi-
	      ronment.

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

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Committed 		   |
       +-----------------------------+-----------------------------+
       |Standard		     |See standards(5). 	   |
       +-----------------------------+-----------------------------+

SEE ALSO
       csh(1), jobs(1), ksh(1), ksh93(1), sh(1), attributes(5), environ(5), standards(5)

SunOS 5.11				   13 Mar 2008					  wait(1)


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