I am trying to execute the cat command from my C# code, but I am running into problems.
So, this is just a very simple test, but I end up with the error:
Error: cat: '>': No such file or directory
Now... both source and target files actually exist.. and same result if target file does not exist.
If I open a console on my Raspberry Pi, it executes just fine. Any help is much appreciated.
My code:
var srcFile = "/home/pi/tm-satellite/Helpers/wpa_supplicant.conf";
var outFile = "/home/pi/tm-satellite/network-test.txt";
StringBuilder sb = new StringBuilder();
var info = new ProcessStartInfo();
info.FileName = "/bin/bash";
info.Arguments = $"-c 'cat {srcFile} > {outFile}'";
info.UseShellExecute = false;
info.CreateNoWindow = true;
info.RedirectStandardOutput = true;
info.RedirectStandardError = true;
var p = Process.Start(info);
//* Read the output (or the error)
sb.AppendLine($"Args: {info.Arguments}");
sb.AppendLine($"Output: {p!.StandardOutput.ReadToEnd()}");
sb.AppendLine($"Error: {p!.StandardError.ReadToEnd()}");
p!.WaitForExit();
return $"Overwrite system file {path}: {p.ExitCode}{Environment.NewLine}{sb}";
CodePudding user response:
This is because you're passing the cat
program the >
argument.
>
only makes sense in bash
or sh
process where it tells to the interpreter that stdout
outputs should be dumped into file
. It's not a valid argument for cat
.
To get around this, invoke your cat
process within your shell:
sh -c 'cat file1 > file2'
In C#
var srcFile = "/home/pi/tm-satellite/Helpers/wpa_supplicant.conf"
var outFile = "/home/pi/tm-satellite/network-test.txt"
var info = new ProcessStartInfo();
info.FileName = "sh";
info.Arguments = $"-c 'cat {srcFile} > {outFile}'";
Alternatively you can use C#'s File
utilities to read the first file and write its contents into the second as it might be faster due to less I/O operations.
I've fixed my sample. Use double quotes instead of single quotes:
var srcFile = "~/bad";
var outFile = "~/good";
var pInfo = new ProcessStartInfo()
{
FileName = "sh",
Arguments = $"-c \"cat {srcFile} > {outFile}\""
};
var process = Process.Start(pInfo);
process.WaitForExit();