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 OSF1
wait
wait(1) General Commands Manual wait(1)NAME
wait - Awaits process completion
SYNOPSIS
wait [pid]
Note
The C shell has a built-in version of the wait command. If you are using the C shell, and want to guarantee that you are using the command
described here, you must specify the full path /usr/bin/wait. See the csh(1) reference page for a description of the built-in command.
STANDARDS
Interfaces documented on this reference page conform to industry standards as follows:
wait: XCU5.0
Refer to the standards(5) reference page for more information about industry standards and associated tags.
OPTIONS
None
OPERANDS
One of the following: The unsigned decimal integer process ID of a command, for which the utility is to wait for the termination. 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 invoca-
tions of wait in the current shell execution environment. The exit status of wait is determined by the last command in the pipeline.
DESCRIPTION
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 waits until all process IDs known to the invoking shell have terminated and exits with
a zero exit status.
If one or more pid operands are specified that represent known process IDs, the wait utility waits until all of them have terminated. If
one or more pid operands are specified that represent unknown process IDs, wait treats them as if they were known process IDs 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 operand.
The known process IDs are applicable only for invocations of wait in the current shell execution environment.
RESTRICTIONS
If wait is called in a subshell or separate utility execution environment, such as one of the following, it returns immediately because
there are no known process IDs to wait for in those environments:
(wait) nohup wait ... find . -exec wait ... ; If the exit status of wait is greater than 128, there is no way for the application
to know if the waited-for process exited with that value or was killed by a signal. Since most utilities exit with small values,
there is seldom any ambiguity.
EXIT STATUS
If one or more parameters were specified, all of them have terminated or were not known by the invoking shell, and the status of the last
parameter specified is known, then the exit status of wait is the exit status information of the command indicated by the last parameter
specified. If the process terminated abnormally due to the receipt of a signal, the exit status is greater than 128 and is distinct from
the exit status generated by other signals. (See the kill -l option.) Otherwise, the wait utility exits with one of the following values:
The wait utility was invoked with no operands and all process IDs known by the invoking shell have terminated. The wait utility detected
an error. The command identified by the last pid operand specified is unknown.
EXAMPLES
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 using kill as shown by the following script:
sleep 1000& pid=$! kill -kill $pid wait $pid echo $pid was terminated by a SIG$(kill -l $?) signal. If either sequence of commands
shown on the first two lines is run in less than 31 seconds either of the commands shown on lines 3 and 4 will return the exit sta-
tus of the second sleep in the pipeline:
sleep 257 | sleep 31 & jobs -l %% wait <pid of sleep 31> wait %%
ENVIRONMENT VARIABLES
The following environment variables affect the execution of wait: Provides a default value for the internationalization variables that are
unset or null. If LANG is unset or null, the corresponding value from the default locale is used. If any of the internationalization vari-
ables contain an invalid setting, the utility behaves as if none of the variables had been defined. If set to a non-empty string value,
overrides the values of all the other internationalization variables. Determines the locale for the interpretation of sequences of bytes
of text data as characters (for example, single-byte as opposed to multibyte characters in arguments). Determines the locale used to
affect the format and contents of diagnostic messages written to standard error. Determines the location of message catalogues for the
processing of LC_MESSAGES.
SEE ALSO
Commands: bg(1), csh(1), fg(1), jobs(1), kill(1), ksh(1), sh(1)
Functions: wait(2)
Standards: standards(5)wait(1)