linux

Cannot use mkdir in home directory: permission denied (Linux Lubuntu)

As @kirbyfan64sos notes in a comment, /home is NOT your home directory (a.k.a. home folder): The fact that /home is an absolute, literal path that has no user-specific component provides a clue. While /home happens to be the parent directory of all user-specific home directories on Linux-based systems, you shouldn’t even rely on that, given that this differs across platforms: for instance, the equivalent directory on macOS is /Users. What all Unix … Read more

Need a good hex editor for Linux

Bless is a high quality, full featured hex editor. It is written in mono/Gtk# and its primary platform is GNU/Linux. However it should be able to run without problems on every platform that mono and Gtk# run. Bless currently provides the following features: Efficient editing of large data files and block devices. Multilevel undo – redo … Read more

Docker can’t connect to docker daemon

After I update my Docker version to 0.8.0, I get an error message while entering sudo docker version: And I’ve followed the instructions and entered command sudo docker -d, and I got this: How do I solve the problem?

Using O_RDWR vs O_RDONLY | O_WRONLY

O_RDONLY | O_WRONLY (at least on my Linux machine) is not the same thing as O_RDWR. The fact that it works seems like a bug/feature/coincidence rather than “it works because it should work that way”.

Hadoop “Unable to load native-hadoop library for your platform” warning

I assume you’re running Hadoop on 64bit CentOS. The reason you saw that warning is the native Hadoop library $HADOOP_HOME/lib/native/libhadoop.so.1.0.0 was actually compiled on 32 bit. Anyway, it’s just a warning, and won’t impact Hadoop’s functionalities. Here is the way if you do want to eliminate this warning, download the source code of Hadoop and recompile libhadoop.so.1.0.0 on 64bit … Read more

Ubuntu: OpenJDK 8 – Unable to locate package

UPDATE: installation without root privileges below I advise you to not install packages manually on ubuntu system if there is already a (semi-official) repository able to solve your problem. Further, use Oracle JDK for development, just to avoid (very sporadic) compatibility issues (i’ve tried many years ago, it’s surely better now). Add the webupd8 repo to your … Read more

How does “cat << EOF" work in bash?

This is called heredoc format to provide a string into stdin. See https://en.wikipedia.org/wiki/Here_document#Unix_shells for more details. From man bash: Here Documents This type of redirection instructs the shell to read input from the current source until a line containing only word (with no trailing blanks) is seen. All of the lines read up to that point are then used as the … Read more

Building HelloWorld C++ Program in Linux with ncurses

I successfully ran sudo apt-get install libncurses5-dev Within my Eclipse window I then try to build the following HelloWord.cpp program: I get the following error: It looks like the compiler is searching for the ncurses library and can’t find it? I checked /usr/lib and the library does not exist there so do I need to manually link the ncurses library … Read more

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