How to redirect stderr to null in cmd.exe
Your DOS command 2> nul Read page Using command redirection operators. Besides the “2>” construct mentioned by Tanuki Software, it lists some other useful combinations.
stderr
Piping both stdout and stderr in bash?
(Note that &>>file appends to a file while &> would redirect and overwrite a previously existing file.) To combine stdout and stderr you would redirect the latter to the former using 1>&2. This redirects stdout (file descriptor 1) to stderr (file descriptor 2), e.g.: $ { echo “stdout”; echo “stderr” 1>&2; } | grep -v … Read more
How do I write to standard error in PowerShell?
Use Write-Error to write to stderr. To redirect stderr to file use: Write-Error “oops” 2> /temp/err.msg or exe_that_writes_to_stderr.exe bogus_arg 2> /temp/err.msg Note that PowerShell writes errors as error records. If you want to avoid the verbose output of the error records, you could write out the error info yourself like so: PS> Write-Error “oops” -ev … Read more
Why does “git submodule add …” write to stderr rather than stdout?
This is not limited to submodules, as noted here: The registration of the submodule will be reported to stderr, as that is consistent with the rest of progress reporting within Git. This helps us in a later patch when we want to reuse the init_submodule function in update_clone whose stdout will be piped to shell … Read more
Why does ‘java -version’ go to stderr?
Is there any special reason for the results of java -version going to stderr? AFAIK, there is no special reason. It is just how the java command was / is implemented. Probably all the way back to Java 1.0, though it would be very difficult to verify that. My brief investigation shows that this behavior … Read more
redirect stdout/stderr to a string
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
Python read from subprocess stdout and stderr separately while preserving order
The code in your question may deadlock if the child process produces enough output on stderr (~100KB on my Linux machine). There is a communicate() method that allows to read from both stdout and stderr separately: from subprocess import Popen, PIPE process = Popen(command, stdout=PIPE, stderr=PIPE) output, err = process.communicate() If you need to read … Read more
Shell redirection i/o order
The Bash manual has a clear example (similar to yours) to show that the order matters and also explains the difference. Here’s the relevant part excerpted (emphasis mine): Note that the order of redirections is significant. For example, the command ls > dirlist 2>&1 directs both standard output (file descriptor 1) and standard error (file … Read more
How to redirect both stdout and stderr to a file [duplicate]
If you want to log to the same file: command1 >> log_file 2>&1 If you want different files: command1 >> log_file 2>> err_file
Bash script – store stderr in a variable [duplicate]
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