How to parallel several jobs in bash

lehe · 07-14-2009, 12:02 PM

Hi,

I wonder how to in a bash script(or other languages if more convenient and/or fast) manage independent jobs(executables with command line arguments) and make them run in parallel? Is there a way to create several sub-process without waiting them to finish?

Which one is faster: multi-threading or multi-process?

Thanks and regards!

MK27 · 07-14-2009, 01:15 PM

You can put a command into the background:

./myscript.sh &

This forks() and returns the command prompt right away *before* the script finishes, so you can start another one right away. You can put a string of these in a file:

Code:

#!/bin/bash

/home/user/bin/myscript1.sh &
/home/user/bin/myscript2.sh &
/home/user/bin/myscript3.sh &

and run that and all three will start almost simultaneously, ie, run in parallel.

lehe · 07-14-2009, 01:43 PM

Thanks!
is running background slower than foreground?

MK27 · 07-14-2009, 01:47 PM

Quote:

Originally Posted by lehe

Thanks!
is running background slower than foreground?

AFAIK there is no reason for it to be, depending on the console interaction and how the script is written it could be faster, but it should be the same generally.

Kennedy · 07-15-2009, 03:08 PM

The only issue would be a race condition for resources. If you have many processes fighting for the same disc, for example, then your overall performance will decline. Otherwise, each process will get a time slice for each task.

07-14-2009, 12:02 PM	#1
lehe Registered User Join Date: Jan 2009 Posts: 159	How to parallel several jobs in bash Hi, I wonder how to in a bash script(or other languages if more convenient and/or fast) manage independent jobs(executables with command line arguments) and make them run in parallel? Is there a way to create several sub-process without waiting them to finish? Which one is faster: multi-threading or multi-process? Thanks and regards!
lehe is offline

07-14-2009, 01:15 PM	#2
MK27 mastering the obvious Join Date: Jul 2008 Location: SE Queens Posts: 5,068	You can put a command into the background: ./myscript.sh & This forks() and returns the command prompt right away before the script finishes, so you can start another one right away. You can put a string of these in a file: Code: #!/bin/bash /home/user/bin/myscript1.sh & /home/user/bin/myscript2.sh & /home/user/bin/myscript3.sh & and run that and all three will start almost simultaneously, ie, run in parallel. __________________ “The essential element in the black art of obscurantism is not that it wants to darken individual understanding, but that it wants to blacken our picture of the world, and darken our idea of existence.” [Friedrich Wilhelm Nietzsche, 1878]
MK27 is offline

07-14-2009, 01:43 PM	#3
lehe Registered User Join Date: Jan 2009 Posts: 159	Thanks! is running background slower than foreground?
lehe is offline

07-15-2009, 03:08 PM	#5
Kennedy Jaxom's & Imriel's Dad Join Date: Aug 2006 Location: Alabama Posts: 863	The only issue would be a race condition for resources. If you have many processes fighting for the same disc, for example, then your overall performance will decline. Otherwise, each process will get a time slice for each task.
Kennedy is offline

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