Is there a bash command that waits for a window to open? Right now I'm doing something along the lines of:
open-program
sleep 100 # Wait for the program to open
send-keyboard-input
Is there a way to have "send-keyboard-input" wait until open-program finishes, eliminating the sleep 100? The time always varies, sometimes it's 90 seconds, sometimes it's 50 second.
Have you tried this?
open-program && send-keyboard-input
Related
while looking on how to parallelize bash tasks, I've stumbles over a code like this:
for item in "${items[#]}"
do
((i=i%THREADS)); ((i++==0)) && wait
process_item $item &
done
Where process_item is some king of function/program that works with item and the THREADS var contain the maximum number of background processes that can run simultaneously.
Can someone explain to me how this works? I understand that i=i%THREADS ensures that i is between 0 and THREADS-1, and that i++==0 increments i and checks whether it is 0. But is wait bound to all sub processes? Or how does it know that is has to wait until the previous batch stopped processing?
It's an obfuscated way of writing
for item in "${items[#]}"
do
# Every THREADSth job, stop and wait for everything
# to complete.
if (( i % THREADS == 0 )); then
wait
fi
((i++))
process_item $item &
done
It also doesn't actually work terribly well. It doesn't ensure that there are always $THREADS jobs running, only that no more than $THREADS jobs are running at once.
i++==0 checks and increments, not the opposite. wait waits for all currently active child processes. So, each iteration (but the first, thanks to the ((i++==0))) first waits for the process launched by the previous iteration and launches a new process.
As I said in the title i have a batch file with echo lines. I want them to stay each on the screen for a certain period of time. Could you give me an exemple of such?
You can do this using sleep command. For example:
SLEEP 5
This will delay the execution for 5 seconds.
I am getting into ruby and have been using threads for a little while now with out fully understanding them. I notice that when adding a thread to an array and if I add a sleep() command as the first command the thread does not run until I do a join which is mostly what I want. So I have 2 questions.
1.Is that suppose to happen?
2.Is there a better way to do that other then the way I'm doing it. Here is a sample code that I have to show what I'm talking about.
job = Array.new
10.times do |n|
job << Thread.new do
sleep 0.001
puts "done #{n}"
end
end
#job.each do |t|
#t.join
#end
puts "End of script"
Output is
End of script
If I remove the comments output is
done 1
done 0
done 7
done 6
done 5
done 4
done 3
done 2
done 9
done 8
End of script
So I use this now but I don't understand why it does that. Sometimes I notice even doing something like `echo hi` instead of sleep does the trick.
Thanks in advance.
Timing of threads isn't a defined behavior. Once you put them to sleep, they will be put in a queue to be run later. You can't ever expect it to run one way or another.
Your main program doesn't take very long to run, so it is likely to happen to finish before your other threads get picked back up to run again. Really, when you think about it, 0.001 seconds is quite a long time to computer, so spinning off 10 threads in that time is likely to happen -- but even if it takes longer, there is no guarantee the thread will resume immediately after .001 seconds. Often there's really no guarantee it won't start before .001 seconds, either, but sleep calls usually don't end early.
When you add the join calls, you are introducing additional time into your main thread which allows the other threads time to run, so this behavior is expected.
Is there any notable difference between
sleep 10
and
wait_until(10)
They both seem to do the same thing: wait 10 seconds then proceed to the next step
sleep just does nothing for the specified time. wait_until takes a block. It waits until the block evaluates to true or times out. If no block is given they act the same.
I have two VBScripts. ScriptA calls ScriptB using the command below
C:\Windows\System32\wscript.exe"" //Nologo //B ""C:\Program Files\ROC\ScriptB.vbs
From the ScriptA log file I can see at every run there is a delay of 5 seconds in starting ScriptB. Both scripts runs on Windows XP.
Is this a default behaviour? how can I change this?
Windows XP won't add a delay to the start of the second script. There may be a delay if the system is under extremely heavy load, but doubtful with just a vbscript.
The best way to determine where your delay is coming from is to search through scriptA and see if you can find any Sleep methods being used. Sleep takes in an argument that tells it to pause for that many milliseconds, so you would pause for 5 seconds if you had a Sleep(5000) statement somewhere in your code.
If sleep is not being called, then most likely scriptA is just finishing up some code that doesn't log out to the log file before scriptB gets kicked off. If you want to determine the exact point of the delay, start at the point in scriptA where you call scriptB and add a two log statements that will print out the time to the log file. Slowly move the first log statement upwards away from the point where scriptB is called and you will be able to determine which code is taking 5 seconds to process before scriptB is started.