how to make batch wait for multiple subprocesses

问题

I have this batch file:

SET WINRAR="C:\Program Files (x86)\WinRAR"
start "" %WINRAR%\WinRAR.exe a -u -m5 "Group 1.rar" "Group 1" "Group 1"
start "" %WINRAR%\WinRAR.exe a -u -m5 "Group 2.rar" "Group 2" "Group 2"
start "" %WINRAR%\WinRAR.exe a -u -m5 "Group 3.rar" "Group 3" "Group 3"
start "" "D:\"

I want all the rar processes to work at the same time and to open the directory D:\ after rar finishes.

回答1:

You can achieve this by starting your un-rar processes without /WAIT and check whether they're finished using tasklist:

@ECHO OFF
SET WINRAR="C:\Program Files (x86)\WinRAR"
start "" %WINRAR%\WinRAR.exe a -u -m5 "Group 1.rar" "Group 1" "Group 1"
start "" %WINRAR%\WinRAR.exe a -u -m5 "Group 2.rar" "Group 2" "Group 2"
start "" %WINRAR%\WinRAR.exe a -u -m5 "Group 3.rar" "Group 3" "Group 3"

:LOOP
tasklist /FI "IMAGENAME eq WinRAR.exe" 2>NUL | find /I /N "WinRAR.exe">NUL
if %ERRORLEVEL%==0 (
    ping localhost -n 6 >nul
    GOTO LOOP
)
start "" "D:\"

The code does the following:

First you start all your un-rar processes. Then you check whether your tasklist contains any winrar.exe processes. If it is the case you wait 5 seconds and check again. As soon as there are no more winrar.exe entries in the task list you go on to start "" "D:\".

EDIT: As you've asked what how wait by ping works, here is the explanation. Sorry, there was a bug in my code. It's ping localhost -n 6 and not ping localhost -6.

ping localhost -n 6>nul makes your system ping localhost 6 times with 1 second between each ping. 6 pings with 1 second between is 5 :) As localhost responds within 1 ms you are waiting about 5 seconds. >nul suprsses the output of the ping command in your console.

回答2:

I'm afraid the solution is not affordable from a batch file only. The options you have pass by thinking outside the box and implement a program who do the job.

For instance, a good implementation could be using the app.activate method who allow you to check if there is a window with certain name "alive".

If you opt for following this path, the solution would be to create a vbs file called "waitForAll.vbs" (for instance) and provide something like this:

Dim objShell
dim found
dim nCount

Set objShell = CreateObject("WScript.Shell")

found = true 
nCount = 100  ' to avoid hangings
do while found and nCount > 0 
   found = objShell.appActivate("CAPTION OF YOUR WINRAR WINDOWS")
   wscript.sleep 5 * 1000 ' sleep for five seconds 
   nCount = nCount - 1
loop ' found 

if not found then 
  ' launch whatever
end if ' not found

And instead of that start "" d:\ you have to insert a call to this "waitForAll.vbs" program: the program will look for all the windows in the userspace that are called similar that the ones of the winrar: when they aren't found, it will start whatever you want.

Optionally, if a winrar window hangs (with a popup message or something like that), this program eventually end via the nCount counter.

来源：https://stackoverflow.com/questions/30368450/how-to-make-batch-wait-for-multiple-subprocesses

标签

batch-file

cmd

wait