Never thought about it, but why not write the usage instructions to stderr if the program was called with no or wrong arguments, and write it to stdout when called with a –help (or similar) argument? This way, if the usage is shown because of an error, it goes to stderr, and if it’s not … Read more
To save both stdout and stderr to a variable: MYVARIABLE=”$(path/myExcecutable-bin 2>&1)” Note that this interleaves stdout and stderr into the same variable. To save just stderr to a variable: MYVARIABLE=”$(path/myExcecutable-bin 2>&1 > /dev/null)”
There’s a really ugly way to capture stderr and stdout in two separate variables without temporary files (if you like plumbing), using process substitution, source, and declare appropriately. I’ll call your command banana. You can mimic such a command with a function: banana() { echo “banana to stdout” echo >&2 “banana to stderr” } I’ll … Read more
Try redirecting stderr to stdout and using $() to capture that. In other words: VAR=$((your-command-including-redirect) 2>&1) Since your command redirects stdout somewhere, it shouldn’t interfere with stderr. There might be a cleaner way to write it, but that should work. Edit: This really does work. I’ve tested it: #!/bin/bash BLAH=$(( ( echo out >&1 echo … Read more
The only cross platform method I found which works in both interactive and non-interactive shells is: command | tee >(cat 1>&2) The argument to tee is a file or file handle. Using process substitution we send the output to a process. In the process =cat=, we redirect stdout to stderr. The shell (bash/ksh) is responsible … Read more
Yes, you can redirect it to an std::stringstream: std::stringstream buffer; std::streambuf * old = std::cout.rdbuf(buffer.rdbuf()); std::cout << “Bla” << std::endl; std::string text = buffer.str(); // text will now contain “Bla\n” You can use a simple guard class to make sure the buffer is always reset: struct cout_redirect { cout_redirect( std::streambuf * new_buffer ) : old( … Read more
If you want to execute a command, and get both stderr and stdout, not “merged”, a solution would probably to use proc_open, which provides a great level of control over the command that’s being executed — including a way to pipe stdin/stdout/stderr. And here is an example : let’s consider we have this shell-script, in … Read more
Googletest offers functions for this: testing::internal::CaptureStdout(); std::cout << “My test”; std::string output = testing::internal::GetCapturedStdout();
You can also put the redirection logic in a contextmanager. import os import sys class RedirectStdStreams(object): def __init__(self, stdout=None, stderr=None): self._stdout = stdout or sys.stdout self._stderr = stderr or sys.stderr def __enter__(self): self.old_stdout, self.old_stderr = sys.stdout, sys.stderr self.old_stdout.flush(); self.old_stderr.flush() sys.stdout, sys.stderr = self._stdout, self._stderr def __exit__(self, exc_type, exc_value, traceback): self._stdout.flush(); self._stderr.flush() sys.stdout = self.old_stdout sys.stderr … Read more