Cannot get output from cmd.exe execution

Question

The code is as follows:

ProcessStartInfo startInfo = new ProcessStartInfo("cmd", "/c" + command);
startInfo.CreateNoWindow = true;
startInfo.UseShellExecute = false;
startInfo.WindowStyle = ProcessWindowStyle.Normal;
startInfo.Arguments = arguments;
startInfo.RedirectStandardError = true;
startInfo.RedirectStandardOutput = true;

Process process = Process.start(startInfo);
StreamReader srOutput = process.StandardOutput;
string output = srOutput.ReadToEnd();

The command is rmdir /s /q 123

I expect to get "The system cannot find the file specified" inside the variable output because "123" is a file path that doesn't exist. But output is an empty string. Why and how should I go about getting the output?

still got doubts, see comment below...

yeeen
– yeeen

2011-06-02 07:17:42 +00:00
Commented Jun 2, 2011 at 7:17 — yeeen
– yeeen, Commented Jun 2, 2011 at 7:17

Andrew Cooper · Accepted Answer · 2011-06-02 05:55:15Z

5

The message you're expecting to see will be onStandardError, not StandardOutput.

answered Jun 2, 2011 at 5:55

Andrew Cooper

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4 Comments

yeeen Over a year ago

Why is it sometimes the expected error msg is in the output instead? For example the MOVE command, if I didn't put the open and close inverted commas for destination path. The "The syntax if the command is incorrect" msg is in the 'StandardOutput' instead of the 'StandardError' and the 'StandardError' is empty.

Hans Passant Over a year ago

You are using the command line processor. Having a user mis-type a command is perhaps far too common to call it an error. Just don't use cmd.exe to do this, use the classes in the System.IO namespace instead.

Andrew Cooper Over a year ago

@yeeen - Just inconsistency on the part of Microsoft in writing the code that executes the commands.

yeeen Over a year ago

@Hans What do u mean by "use the classes in the System.IO namespace" instead?

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