c# redirect (pipe) process output to another process

Question

I am trying to run a process in c# using the Process class.

Process p1  = new process();
p1.startinfo.filename =  "xyz.exe";
p1.startinfo.arguments = //i am building it based on user's input.
p1.start();

So based on user input i am building the argument value. Now i have a case where i have to pipe the output of p1 to another process say grep. so i basically tried this

p1.startinfo.arguments = "-info |grep 1234" ;

what i intended is something like xyz.exe -info|grep 1234

but this doesn't seem to work in .net .. I can actually create another process variable and run "grep" as a separate process.. But i was wondering if there is any way to do as iam trying out above..

Answer 1

The much easier way would be to do just use cmd as your process.

Process test = new Process();
test.StartInfo.FileName = "cmd";
test.StartInfo.Arguments = @"/C ""echo testing | grep test""";
test.Start();

You can capture the output or whatever else you want like any normal process then. This was just a quick test I built, but it works outputting testing to the console so I would expect this would work for anything else you plan on doing with the piping. If you want the command to stay open then use /K instead of /C and the window will not close once the process finishes.

Answer 2

You can use CliWrap to make piping really easy, without the overhead of a console, and also completely x-platform:

var output = File.Create("output.txt"); // stream is just one of the options

var cmd = Cli.Wrap("xyz.exe") | output;
await cmd.ExecuteAsync();