Waiting for an arbitrary background process (limiting number of jobs running)
Hi,
I'm trying to write a script to decompress a directory full of files. The decompression commands can run in the background, so that many can run at once. But I want to limit the number running at any one time, so that I don't overload the machine.
Something like this:
At the marked spot, I want to wait for one of my background processes to complete. I don't mind which one, but I do want to wait for just one.
wait doesn't work, as it waits for all jobs to complete. On the other hand, wait N doesn't work, because I don't know which job will finish first.
I could use trap "..." 20, but I'd need to be able to pause my script at the XXX line and be able to resume it via the "..." from the trap command. I can't think of a way of doing this ("suspend" in bash might work, but really I need this to work in ksh - I'm not sure the server this will ultimately run on has bash installed).
I'm trying to install a solaris 9 patch cluster and when I try to use & to run in background it won't allow me to enter in my sudo password so it fails the install and sudo auth. Does Solaris not have screen like linux? If & will work what am I doing wrong?
sudo ./install_cluster -q &
is... (3 Replies)
I have the following sample script to run a script the jobs with the same
priority(in this case field3) in parallel; wait for the jobs to finish
and run the next set of jobs in parallel.When all the lines are read
exit the script.
I have the following script which is doing evrything I want... (1 Reply)
i need to execute 5 jobs at a time in background and need to get the exit status of all the jobs i wrote small script below , i'm not sure this is right way to do it.any ideas please help.
$cat run_job.ksh
#!/usr/bin/ksh
####################################
typeset -u SCHEMA_NAME=$1
... (1 Reply)
Hi All,
I have requirement. I am running a job every 30mins. before starting the process, i need to check the process, if the process is still running then i need not trigger the process again, if it is not running then trigger the process again. I am using cron to trigger the shell script. Can... (7 Replies)
Hello,
I am a novice shell script programmer. And facing this problem any help is appreciated.
I m writing a shell script and running few commands in it background as I have to run them simultaneously.
Sample code :
sql_prog &
sql_prog &
sql_prog &
echo "Process Completed"
Here... (2 Replies)
Hi,
I have on shell script which internally calls more than one scripts which run in background.
These scripts cannot be modified to run in foreground.
eg. myscript.sh -> bulk_launcher.sh -> acq_launcher.sh
-> bulk_loader.sh
I want the calling shell script myscript.sh to wait till the... (7 Replies)
Hello,
I am running GNU bash, version 3.2.39(1)-release (x86_64-pc-linux-gnu). I have a specific question pertaining to waiting on jobs run in sub-shells, based on the max number of parallel processes I want to allow, and then wait... (1 Reply)
Hi ,
I want to see all the background process that are running in unix box machine...please guide me is there any specific command for that..since I am executing some scripts at background..!!:confused: (1 Reply)
Hi,
I have this simple c program that creates duplicate process with fork():
#include <sys/types.h>
main()
{
if (fork() == 0)
while(1);
else
while(1);
}
I tried running it in the background
gcc -o test first.c
test &
And I got this list of running process: (4 Replies)
Discussion started by: uniran
4 Replies
LEARN ABOUT SUNOS
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)