fatal: ambiguous argument '>' error when executing git diff from C# directly

Question

I am trying to do the following in C#:

Get the difference between two branches.
Redirect the output in a patch file.
Checkout a new empty branch.
Apply the patch file to this new branch.
Add files & commit this branch to the remote repo.

The current git commands I am running:

git checkout branch2
git diff branch1 > delta.patch
git checkout --orphan delta_branch 
git rm -rf . 
git apply delta.patch
git add -A  
git commit -m "Adding a temporary branch.." 
git push -u origin delta_branch

While this works fine from the git bash, it does not when executing it from C# and I get the following message for the diff command:

git diff branch1 > delta.patch

EDIT:

The C# method I am using to run each of the above mentioned commands is the following:

public void ExecuteGitCommand(string sourceDirectory, string gitExePath, string command)
        {
            ProcessStartInfo gitInfo = new ProcessStartInfo();
            gitInfo.CreateNoWindow = true;
            gitInfo.RedirectStandardError = true;
            gitInfo.RedirectStandardOutput = true;
            gitInfo.FileName = gitExePath;
            gitInfo.UseShellExecute = false;

            Process gitProcess = new Process();

            gitInfo.Arguments = command;
            gitInfo.WorkingDirectory = sourceDirectory;

            gitProcess.StartInfo = gitInfo;
            gitProcess.Start();

            string output;
            string error;

            using (StreamReader streamReader = gitProcess.StandardOutput)
            {
                output = streamReader.ReadToEnd();
            }

            using (StreamReader streamReader = gitProcess.StandardError)
            {
                error = streamReader.ReadToEnd();
            }

            Console.WriteLine("Output:");
            Console.WriteLine(output);

            if (!string.IsNullOrEmpty(error))
            {
                Console.WriteLine("Error:");
                Console.WriteLine(error);
            }

            gitProcess.WaitForExit();
            gitProcess.Close();
        }

And it is called like this:

string[] commands = new string[] { gitCheckout, gitDiff, gitCheckoutDelta, gitRmDeltaFiles, gitApplyPatch, gitAdd, gitCommit, gitPush };

foreach(string command in commands)
 {
     Console.WriteLine(command); //debug only
     ExecuteGitCommand(sourceDirectory, gitExePath, command);
 }

Note: I am using LibGit2Sharp in other parts of my project but in this specific case I cannot make use of it, since LibGit2Sharp does not implement git-apply.

Can you show your code? It sounds like you're trying to redirect directly in `Process.Start`. (Instead, you need to make sure you set `ProcessStartInfo.RedirectStandardOutput`.) — Edward Thomson, May 02 '18 at 15:47

score 2 · Accepted Answer · answered May 02 '18 at 15:50

You cannot simply redirect to a file in the Process.Start information. That's a shell operation, not something that you can simply invoke. Instead, you'll need to read the git application's standard output yourself. For example:

ProcessStartInfo startInfo = new ProcessStartInfo();
startInfo.UseShellExecute = false;

startInfo.RedirectStandardInput = true;
startInfo.RedirectStandardOutput = true;
startInfo.RedirectStandardError = true;

startInfo.FileName = "git.exe";
startInfo.Arguments = "diff branch1";

Process process = new Process();
process.StartInfo = startInfo;
process.Start();

while ((line = process.StandardOutput.ReadLine()) != null)
{
     // This is the output you're reading...
}

fatal: ambiguous argument '>' error when executing git diff from C# directly

1 Answers1