Say, if I have
- foo.exe
- bar.exe
- baz.exe
How do I run all of them from a batch file asynchronously, i.e. without waiting for the previous program to stop?
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7 Answers
Using the START command to run each program should get you what you need:
START "title" [/D path] [options] "command" [parameters]
Every START invocation runs the command given in its parameter and returns immediately, unless executed with a /WAIT switch.
That applies to command-line apps. Apps without command line return immediately anyway, so to be sure, if you want to run all asynchronously, use START.
4 Comments
RichN
Okay, thanks. I should have read each entry of
help carefully. :)
Joey
Shameless self-advertising: I once created a batch which is able to function as some kind of thread pool, just for processes: stackoverflow.com/questions/672719/…
Pierluigi
If you need to provide arguments or if the path to the commands contains spaces remember to add quotes. In this case you also need to provide a title for the opening console window: start "" "[path to command]" [command args]
Martin Prikryl
"Apps without command line return immediately anyway" – Are you sure? Why GUI application blocks a batch file?
Combining a couple of the previous answers, you could try start /b cmd /c foo.exe.
For a trivial example, if you wanted to print out the versions of java/groovy/grails/gradle, you could do this in a batch file:
@start /b cmd /c java -version
@start /b cmd /c gradle -version
@start /b cmd /c groovy -version
@start /b cmd /c grails -version
If you have something like Process Explorer (Sysinternals), you will see a few child cmd.exe processes each with a java process (as per the above commands). The output will print to the screen in whatever order they finish.
start /b : Start application without creating a new window. The
application has ^C handling ignored. Unless the application
enables ^C processing, ^Break is the only way to interrupt
the application
cmd /c : Carries out the command specified by string and then terminates
2 Comments
djKianoosh
it prevents the command from being echoed to the console. In batch scripts, sometimes you'll see
echo off at the beginning which, when you execute the script, will prevent all the commands from being echoed to the console. The @ is similar but just for that single command. So, sometimes you'll see @echo off.You can use the start command to spawn background processes without launching new windows:
start /b foo.exe
The new process will not be interruptable with CTRL-C; you can kill it only with CTRL-BREAK (or by closing the window, or via Task Manager.)
4 Comments
user2023370
Where is
BREAK on keyboards these days?
Gerold Broser
@user2023370 Still on the Pause key. Most laptops that lack certain keys support hidden key combinations.
Create a batch file with the following lines:
start foo.exe
start bar.exe
start baz.exe
The start command runs your command in a new window, so all 3 commands would run asynchronously.
1 Comment
works as long as you don't have a path with spaces.. Then when you put double quotes around it, it thinks in a title, not an application. This works. START "VMPlayer" /D "C:\Users\gavin\Virtual Machines\CentOS 8 64-bit" "C:\Program Files (x86)\VMware\VMware Player\vmplayer.exe"
Use the START command:
start [programPath]
If the path to the program contains spaces remember to add quotes. In this case you also need to provide a title for the opening console window
start "[title]" "[program path]"
If you need to provide arguments append them at the end (outside the command quotes)
start "[title]" "[program path]" [list of command args]
Use the /b option to avoid opening a new console window (but in that case you cannot interrupt the application using CTRL-C
Comments
There's a third (and potentially much easier) option. If you want to spin up multiple instances of a single program, using a Unix-style command processor like Xargs or GNU Parallel can make that a fairly straightforward process.
There's a win32 Xargs clone called PPX2 that makes this fairly straightforward.
For instance, if you wanted to transcode a directory of video files, you could run the command:
dir /b *.mpg |ppx2 -P 4 -I {} -L 1 ffmpeg.exe -i "{}" -quality:v 1 "{}.mp4"
Picking this apart, dir /b *.mpg grabs a list of .mpg files in my current directory, the | operator pipes this list into ppx2, which then builds a series of commands to be executed in parallel; 4 at a time, as specified here by the -P 4 operator. The -L 1 operator tells ppx2 to only send one line of our directory listing to ffmpeg at a time.
After that, you just write your command line (ffmpeg.exe -i "{}" -quality:v 1 "{}.mp4"), and {} gets automatically substituted for each line of your directory listing.
It's not universally applicable to every case, but is a whole lot easier than using the batch file workarounds detailed above. Of course, if you're not dealing with a list of files, you could also pipe the contents of a textfile or any other program into the input of pxx2.
3 Comments
Peter M
The latest xargs win32 port works well nowadays (the one included with git for windows anyway).
Gökhan Sever
This is great except it fails dealing with files containing unicode characters. Any plans to support unicode files? Thanks.
moltenform
@GökhanSever In the past I've worked around this issue by using the "short name" form of the path, that looks like C:\PROGRA~1\WINDOW~3\MYPROG~1.EXE. Not pretty, but it works.
I could not get anything to work I ended up just using powershell to start bat scripts .. sometimes even start cmd /c does not work not sure why .. I even tried stuff like start cmd /c notepad & exit
start-Process "c:\BACKUP\PRIVATE\MobaXterm_Portable\MobaXterm_Portable.bat" -WindowStyle Hidden
