Question

I have a C# command-line application that I need to run in windows and under mono in unix. At some point I want to launch a subprocess given a set of arbitrary paramaters passed in via the command line. For instance:

Usage: mycommandline [-args] -- [arbitrary program]

Unfortunately, System.Diagnostics.ProcessStartInfo only takes a string for args. This is a problem for commands such as:

./my_commandline myarg1 myarg2 -- grep "a b c" foo.txt

In this case argv looks like :

argv = {"my_commandline", "myarg1", "myarg2", "--", "grep", "a b c", "foo.txt"}

Note that the quotes around “a b c” are stripped by the shell so if I simply concatenate the arguments in order to create the arg string for ProcessStartInfo I get:

args = "my_commandline myarg1 myarg2 -- grep a b c foo.txt"

Which is not what I want.

Is there a simple way to either pass an argv to subprocess launch under C# OR to convert an arbitrary argv into a string which is legal for windows and linux shell?

Any help would be greatly appreciated.

Answer 1

Thanks to all for the suggestions. I ended up using the algorithm from shquote (http://www.daemon-systems.org/man/shquote.3.html).

/**
 * Let's assume 'command' contains a collection of strings each of which is an
 * argument to our subprocess (it does not include arg0).
 */
string args = "";
string curArg;
foreach (String s in command) {
    curArg = s.Replace("'", "'\\''"); // 1.) Replace ' with '\''
    curArg = "'"+curArg+"'";          // 2.) Surround with 's
    // 3.) Is removal of unnecessary ' pairs. This is non-trivial and unecessary
    args += " " + curArg;
}

I’ve only tested this on linux. For windows you can just concatenate the args.