Windows CMD Batch, START and output redirection

I would like to run two programs simultaneously from a batch file, and redirect the first program's output into a text file like:

start python 1st.py arg1 arg2 > out.txt
start 2nd.exe %1 arg2 arg3

While the programs run as expected, all output is shown on stdout.

Solution 1:

You might need to do it this way:

start cmd /c python 1st.py arg1 arg2 ^> out.txt

Redirection is applied to the start command, but somehow not to the cmd.exe instance it runs.

If the > operator is escaped, everything should work:

start 1st.py arg1 arg2 ^> out.txt

(If you want to redirect stderr as well, use 2^> for it.)

Additionally, if you want to redirect both stderr and stdout this works for me

start call delay.bat ^1^> log.txt ^2^>^&^1

It seems every character basically needs to be escaped. This command normally looks like this:

delay.bat 1> log.txt 2>&1

What did the trick for me was moving the command into a separate batch file:

rem this first batch file triggers the second one:
start the_second.bat arg1 arg2 out.txt

the_second.bat then looks like this:

python 1st.py %1 %2 > %3