In the present scenario although Child2 failed first ( exit 1 ) the status is not displayed until Child1 is complete.
That's because you are waiting for the first child before anything else. You can try plain "wait", but that doesn't return until ALL children have completed.
What you can do is set up a wait-loop, and then set up a signal handler to call "jobs" or check on the specific status of any jobs; and set up an alarm-like thingy to wake up the signal handler. The wait call then gets pre-empted. So for instance, something like this (untested) in bash might work:
When wait exits with 0, there are no remaining background tasks, and the loop terminates. If you don't have bash, but have "setsid", you can effectively disown a process that way.
nohup /bin/bassh $HOME/scripts/test.sh > $HOME/log/test.log 2>&1 &
nohup $HOME/scripts/test.sh > $HOME/log/test.log 2>&1 &
Which is the good practice to run a script in background of above two ?
does the first one will have any overhead on the system ?
our system is SunOS 5.10... (2 Replies)
I have script 3 scripts 1 parent (p1) and 2 children child1 and child2
I have script 3 scripts
1 parent
2 children
child1
child2
In the code below the 2 child processes fire almost Instantaneously in
the background, Is that possible to know the status of pass/fail of each
process... (12 Replies)
Running centos 2.6, I have a bash script in which I'd like to run a number of background threads in parallel, tee'ing the results of the entire script to one file, while tee'ing the result of each background thread to another.
Here's what I'm doing, where the number of csv files control the... (1 Reply)
So I made my own unix shell, but i want to make a background process when using the & appended to the end, so far most of the commands seem to work (except cd, but thats another story)
right now here is what I have got.
Im thinking maybe I shouldn't be using switch and maybe switch it to... (27 Replies)
I am trying to use a loop to start tasks 0-3, running 0,1,2 in the background with &.
FOLDSET=( 0 1 2 3 )
for FOLDSET in ${FOLDSET}
do
if ; then
BACKGRD="&"
else
BACKGRD=""
fi
# start task $FOLDSET
task1 -nogui -ni -p $PROJ \
epochs=$EPOS ... (3 Replies)
NOTE: I am using BASH and Solaris 10 for this.
Currently in the process of building a script that has a main "watcher" daemon that reads a configuration file and starts background processes based on it's global configuration. It is basically an infinite loop of configuration reading. Some of the... (4 Replies)
I'm having trouble with part of this bash script in Linux where I respawn a new instance of script and kill the old one to prevent forking (Yes, I know 'exec' will not fork but this needs to be interactive) When the old instance is kill it pops up "Terminated!" in the middle of the new instance... (7 Replies)
Hi
Say I am interested in processing a big data set over shell, and each process individually takes a long time, but many such processes can be pipe-lined, is there a way to do this automatically or efficiently in shell?
For example consider pinging a list addresses upto 5 times each. Of... (5 Replies)
I'm completely brand new to bash scripting (migrating from Windows batch file scripting). I'm currently trying to write a bash script that will automatically reset "error-disabled" Cisco switch ports. Please forgive the very crude and inefficient script I have so far (shown below). It is... (10 Replies)
Hello! I have got a homework. The bash script runs in the background and checks the user's mailbox and when the user gets a new mail a popup window appears with some text and information about the sender (from who and when).I have no idea how to start, any help would be appreciated! Thank you:) (1 Reply)
Discussion started by: capo2ndfret
1 Replies
LEARN ABOUT XFREE86
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)