How to parallel several jobs in bash

This is a discussion on How to parallel several jobs in bash within the Linux Programming forums, part of the Platform Specific Boards category; Hi, I wonder how to in a bash script(or other languages if more convenient and/or fast) manage independent jobs(executables with ...

  1. #1
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    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!

  2. #2
    spurious conceit MK27's Avatar
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    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.
    C programming resources:
    GNU C Function and Macro Index -- glibc reference manual
    The C Book -- nice online learner guide
    Current ISO draft standard
    CCAN -- new CPAN like open source library repository
    3 (different) GNU debugger tutorials: #1 -- #2 -- #3
    cpwiki -- our wiki on sourceforge

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    Thanks!
    is running background slower than foreground?

  4. #4
    spurious conceit MK27's Avatar
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    Quote Originally Posted by lehe View Post
    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.
    C programming resources:
    GNU C Function and Macro Index -- glibc reference manual
    The C Book -- nice online learner guide
    Current ISO draft standard
    CCAN -- new CPAN like open source library repository
    3 (different) GNU debugger tutorials: #1 -- #2 -- #3
    cpwiki -- our wiki on sourceforge

  5. #5
    {Jaxom,Imriel,Liam}'s Dad Kennedy's Avatar
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    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.

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