Man, this is not so good, because Java is cross-platform and ‘/dev/null’ is Unix specific (apparently there is an alternative on Windows, read the comments). So your best option is to create a custom OutputStream to disable output. try { System.out.println(“this should go to stdout”); PrintStream original = System.out; System.setOut(new PrintStream(new OutputStream() { public void … Read more
From within a Ruby script, you can redirect stdout and stderr with the IO#reopen method. # a.rb $stdout.reopen(“out.txt”, “w”) $stderr.reopen(“err.txt”, “w”) puts ‘normal output’ warn ‘something to stderr’ $ ls a.rb $ ruby a.rb $ ls a.rb err.txt out.txt $ cat err.txt something to stderr $ cat out.txt normal output
On POSIX systems, you can do it as follows: int bak, new; fflush(stdout); bak = dup(1); new = open(“/dev/null”, O_WRONLY); dup2(new, 1); close(new); /* your code here … */ fflush(stdout); dup2(bak, 1); close(bak); What you want is not possible in further generality. Any solution using freopen is wrong, as it does not allow you to … Read more
Do you need to do anything with the output of the process? The check_call method might be useful here. See the python docs here: https://docs.python.org/2/library/subprocess.html#subprocess.check_call You can then use this as follows: try: subprocess.check_call(command) except subprocess.CalledProcessError: # There was an error – command exited with non-zero code However, this relies on command returning an exit … Read more
Clarification: TestText = “Test – āĀēĒčČ..šŠūŪžŽ” # this not UTF-8…it is a Unicode string in Python 3.X. TestText2 = TestText.encode(‘utf8′) # this is a UTF-8-encoded byte string. To send UTF-8 to stdout regardless of the console’s encoding, use the its buffer interface, which accepts bytes: import sys sys.stdout.buffer.write(TestText2)
One thing to also remember, there’s nothing stopping you from writing functions to avoid the boilerplate. For example I have a command line app that uses log and I wrote this function: func captureOutput(f func()) string { var buf bytes.Buffer log.SetOutput(&buf) f() log.SetOutput(os.Stderr) return buf.String() } Then used it like this: output := captureOutput(func() { … Read more
Solution 1: Using process substitution The most convenient way of doing this is by using process substitution. In bash the syntax looks as follows: foo -o >(other_command) (Note that this is a bashism. There’s similar solutions for other shells, but bottom line is that it’s not portable.) Solution 2: Using named pipes explicitly You can … Read more
You can pass stdout and stderr as parameters to Popen() subprocess.Popen(self, args, bufsize=0, executable=None, stdin=None, stdout=None, stderr=None, preexec_fn=None, close_fds=False, shell=False, cwd=None, env=None, universal_newlines=False, startupinfo=None, creationflags=0) For example >>> import subprocess >>> with open(“stdout.txt”,”wb”) as out, open(“stderr.txt”,”wb”) as err: … subprocess.Popen(“ls”,stdout=out,stderr=err) … <subprocess.Popen object at 0xa3519ec> >>>
I like the idea of using freopen. You might also be able to redirect stdout to a pipe using dup and dup2, and then use read to grab data from the pipe. Something like so: #include <stdio.h> #include <stdlib.h> #include <unistd.h> #define MAX_LEN 40 int main( int argc, char *argv[] ) { char buffer[MAX_LEN+1] = … Read more
You might be able to do what you want with VT100 control codes. Something like this maybe: CURSOR_UP_ONE = ‘\x1b[1A’ ERASE_LINE = ‘\x1b[2K’ print(CURSOR_UP_ONE + ERASE_LINE)