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I would like to test in my bash script where stdout and stderr are directed, or more precisely, if they have been redirected. Have you an idea ? The $* bash variable don't give me this info. Mat You should be able to use the -t test switch to tell if the output streams are tty s or not: if [ -t 1 ] ; then echo stdout is a terminal else echo stdout is not a terminal fi Use -t 0 for stdin . Use -t 2 for stderr . Technically there is no way of telling whether stdin/stdout/stderr are "redirected" because you don't know what's invoking your script. If it's not being invoked from another shell,

Given the following answer (first c++11 answer): How to execute a command and get output of command within C++ using POSIX? Here is the implementation for your convinience: #include <cstdio> #include <iostream> #include <memory> #include <stdexcept> #include <string> #include <array> std::string exec(const char* cmd) { std::array<char, 128> buffer; std::string result; std::shared_ptr<FILE> pipe(popen(cmd, "r"), pclose); if (!pipe) throw std::runtime_error("popen() failed!"); while (!feof(pipe.get())) { if (fgets(buffer.data(), 128, pipe.get()) != nullptr) result += buffer.data(); } return

I spent a few angry hours looking for the problem with Unicode strings that was broken down to something that Python (2.7) hides from me and I still don't understand. First, I tried to use u".." strings consistently in my code, but that resulted in the infamous UnicodeEncodeError . I tried using .encode('utf8') , but that didn't help either. Finally, it turned out I shouldn't use either and it all works out automagically. However, I (here I need to give credit to a friend who helped me) did notice something weird while banging my head against the wall. sys.getdefaultencoding() returns ascii ,

I have a simple Android.mk file: LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) $(shell ($(LOCAL_PATH)/echo_test.sh)) LOCAL_MODULE := libecho_test LOCAL_MODULE_TAGS := optional include $(BUILD_SHARED_LIBRARY) The interesting thing that it does is to call the 'echo_test.sh' bash script. In the case when the contents of the script are #!/bin/bash echo 'echo is working' >&2 or #!/bin/bash echo 'echo is working' >/dev/null everything is OK. Things go wrong when the bash script is #!/bin/bash echo 'echo is working' or #!/bin/bash echo 'echo is working' >&1 Then the returned error is Android.mk

I use Vagrant to spawn a standard "precise32" box and provision it with Chef so I can test my Node.js code on Linux when I work on a Windows machine. This works fine. I also have this bash command so it auto installs my npm modules: bash "install npm modules" do code <<-EOH su -l vagrant -c "cd /vagrant && npm install" EOH end This also works fine except that I never see the console output if it completes successfully. But I'd like to see it so we can visually monitor what is going on. This is not specific to npm. I see this similar question with no concrete answers: Vagrant - how to print

I have a file with binary data and I need to replace a few bytes in a certain position. I've come up with the following to direct bash to the offset and show me that it found the place I want: dd bs=1 if=file iseek=24 conv=block cbs=2 | hexdump Now, to use "file" as the output: echo anInteger | dd bs=1 of=hextest.txt oseek=24 conv=block cbs=2 This seems to work just fine, I can review the changes made in a hex editor. Problem is, "anInteger" will be written as the ASCII representation of that integer (which makes sense) but I need to write the binary representation. I want to use bash for this

Original title: " Help me understand this weird Python idiom? sys.stdout = codecs.getwriter('utf-8')(sys.stdout) " I use this idiom all the time to print a bunch of content to standard out in utf-8 in Python 2.*: sys.stdout = codecs.getwriter('utf-8')(sys.stdout) But to be honest, I have no idea what the (sys.stdout) is doing. It sort of reminds me of a Javascript closure or something. But I don't know how to look up this idiom in the Python docs. Can any of you fine folks explain what's going on here? Thanks! .getwriter returns a function callable object; you are merely calling it in the same