Hello all,
Can someone explain to me the advantage between using subshell over a function call in scripts? To me these are the same. Am I wrong to think this? (4 Replies)
I am having a problem getting the PID of a process I start in the background is a csh.
In tcsh and sh it's simple
$! give it to you
But in csh this just returns
Variable syntax
From the man page it should work but it doesn't????
Any help. (2 Replies)
consider the given prg.
main() {
.....
function1(); /* to write into a file or log */
printf(" ");
.....
}
when the control reaches function1(), it should get executed in the
background.At the same time main's printf(" ") statement should also get executed.i.e... (5 Replies)
hello All,
I need to invoke by perl script some program/command and monitor it for 5
minutes . In case it still running for more then 5 min I need to send a signal which will stop it.
I implemeted this as shown below by using eval & alarm
and I'd like to know if there is a better way to... (1 Reply)
Guys,
can you help me in killing the process which is running in back ground under for loop
I am not able to find the PID using ps -afx|grep <word in command I entered> (1 Reply)
Hi all,
I'm reading <advanced bash scripting> and there is a example to kill a background process in a limited time,as shown below:
#! /bin/bash
#set -n
TIMEOUT=$1
count=0
hanging_jobs & {
while ((count < TIMEOUT));do
eval ' && ((count = TIMEOUT))'
((count++))
sleep 1... (6 Replies)
Hello. I was wondering if someone can help me out with something. To simplify my life, I have written a tiny script to open an ssh tunnel through another linux host so that I can access the esxi hosts on that network using the client. For this I have to tunnel ports 443, 902, and 903. Here is what... (1 Reply)
Hey all,
Okay, this one is tricky and I'm not sure there is a niec way to do it, or indeed anyway to do it. The main issue revolves around timing out a hung ssh. I am doing this by creating a wrapper script for the ssh with the following requirements.
My requirements are:
Defineable... (5 Replies)
Here is some back ground on the script. The script is to poll an arbitrary number of DB's. To do this I am creating a function that takes the file_path to the DB and the min poll interval as arguments. The function will be called for each DB and then ran in the background. The function I was... (6 Replies)
Hello All,
I was looking into creating a script that would be used only to start a Daemon and create a lock file...
F.Y.I. It's for Nagios' NRPE Daemon Plugin...
Anyway when I run the command to start the Daemon (below):
/usr/local/nagios/bin/nrpe -c /usr/local/nagios/etc/nrpe.cfg -d
And... (14 Replies)
Discussion started by: mrm5102
14 Replies
LEARN ABOUT X11R4
wait
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
DESCRIPTION
The shell itself executes wait, without creating a new process. If you get the error message cannot fork,too many processes, try using the
wait command to clean up your background 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 status. If pid is omitted, all your shell's currently
active background processes are waited for and the return code will be 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 will return immediately and the return code will be 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 environment.
If the wait utility is invoked with no operands, it will wait 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 will wait until all of
them have terminated. If one or more pid or jobid operands are specified that represent unknown process IDs (or jobids), wait will treat
them as if they were known process IDs (or jobids) that exited with exit status 127. The exit status returned by the wait utility will be
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.
OPERANDS
The following operands are supported:
One of the following:
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 control option.
USAGE
On most implementations, wait is a shell built-in. If it is called in a subshell or separate utility execution environment, such as one of
the following,
(wait)
nohup wait ...
find . -exec wait ... ;
it will return immediately because there will be no known process IDs to wait for in those environments.
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 will return 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_MES-
SAGES, and NLSPATH.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
SEE ALSO csh(1), jobs(1), ksh(1), sh(1), attributes(5), environ(5), standards(5)SunOS 5.10 12 Dec 1997 wait(1)
03-16-2009
A question about the PID of a background function
