windows 10 - wmic output empty when run from batchfile, but contains info when run from cmd

I have this wmic command which finds out the PID of my process and works fine from cmd, but refuses to produce output when executed in a bat-file:

wmic /output:process.pid process where (Name like '%java%' and commandLine like '%part-of-the-path%') get ProcessId

When I run it from cmd, it produces a file containing

ProcessId
19352

The info is followed by two blank lines. When I run it from a batch-file, it only produces a file with two blank lines.

I tried /output:filename, > filename and | more > filename, all with the same result.

Why is this? How to make the command produce output from the batch?

Answer

Just like most of programming languages, a batch file also has escape characters. % sign used in command line is an escape character in batch file and give the command a different meaning. It is actually looking for a variable named %java%.

To resolve this problem, use %% instead of % in batch file. To see more details and information on other escape character look here.

Following command should work in batch file.

wmic /output:process.pid process where (Name like '%%java%%' and commandLine like '%%part-of-the-path%%') get ProcessId