I recently had to do this to get TortoiseMerge working with Mercurial within Cygwin. It turned out to be pretty easy and I couldn’t believe that a lot of people were saying that you had to route the output to a temporary file and then read it back into your program or some such garbage. Anyway, behold!!

for /f "tokens=1" %%A in (
    '"cygpath -w %1"' ) do set TMergePath1=%%A

It’s kind of a hack using the FOR /f but it basically allows you to set the output of a program to a variable. You can even parse the output to pull out a particular piece of the output to put in the variable. This is particularly useful with windows commandline programs which weren’t really made to be piped and redirected.

Anyway, in my case I’m setting the output of cygpath called on a cygwin path to convert it into a windows path and then set the output to the TMergePath variable. The tokens=1 part tells the program that I only want to call the code after do for the first token. In my case there is only one anyway. You can set tokens=1,2,4 if you want to loop for the first, second and forth tokens. You can also set the delimiter like tokens=1,2,4 delims=; if your output looks like token1;token2;token3;token4