Questions tagged [linux]

NOTICE: All Linux questions must be related to programming; those that aren't will be closed. Use this tag only if your question relates to programming using Linux APIs or Linux-specific behavior, not just because you happen to run your code on Linux. If you need Linux support, you can try or the specific Linux distribution's Stack Exchange site like or

GNU/Linux is a Unix-like computer operating system which consists of necessary user-space libraries and programs provided by GNU in Cambridge, Massachusetts and a kernel, developed by Linus Torvalds in Helsinki, Finland.

The GNU/Linux naming controversy is a dispute among members of the free and open-source software community over how to refer to the computer operating system commonly called .


A GNU/Linux-based system is a modular Unix-like operating system. It derives much of its basic design from principles established in Unix during the 1970s and 1980s. Such a system uses a monolithic kernel that handles process control, networking, and peripheral and file system access. Device drivers are either integrated directly with the kernel or added as modules loaded while the system is running.

Separate projects that interface with the kernel provide much of the system's higher-level functionality. The GNU user land is an important part of most GNU/Linux-based systems, providing the most common implementation of the C library, a popular shell, and many of the common Unix tools which carry out many basic operating system tasks. The graphical user interface (or GUI) used by most GNU/Linux systems is built on top of an implementation of the X Window System.

Tag Usage

The tag on Stack Overflow is generally used for questions about:

  • programming against the APIs supplied by the operating system
  • the implementation of the kernel
  • programming tools and techniques for use on a Linux-based system.

Notable questions that probably don't belong are:

  • questions about using a desktop or laptop GNU/Linux system are better directed towards Super User, Unix & Linux, Ask Ubuntu, or Elementary OS if they're specifically about those distributions.
  • questions about administering GNU/Linux systems for other users and networking GNU/Linux systems in a context more complicated than a minimal home network are better directed towards Server Fault.

Many questions about GNU/Linux can also be properly tagged as , but some features are specific to GNU/Linux and are not found on other Unix™ and Unix-like operating systems. If you have questions about a specific distribution and version (e.g., , it may not be necessary to use this tag for that question.

A fair number of questions are questions about the command shell (bash by default on many systems), and are probably better tagged with and/or the particular shell you are interested in (, , , etc.).

Questions about the internals of the Linux kernel or regarding writing Linux kernel modules should be tagged .

Free Linux and GNU/Linux Books

Common GNU/Linux distributions

Distrowatch aggregates new release notices from these and hundreds of other GNU/Linux distributions, Phoronix keeps track of new GNU/Linux features and GNU/Linux Performance.

Other resources

Related tags

226061 questions
55 answers

How to find all files containing specific text (string) on Linux?

How do I find all files containing a specific string of text within their file contents? The following doesn't work. It seems to display every single file in the system. find / -type f -exec grep -H 'text-to-find-here' {} \;
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How can I recursively find all files in current and subfolders based on wildcard matching?

How can I recursively find all files in current and subfolders based on wildcard matching?
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How to change the output color of echo in Linux

I am trying to print a text in the terminal using echo command. I want to print the text in a red color. How can I do that?
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How do I delete an exported environment variable?

Before installing gnuplot, I set the environment variable GNUPLOT_DRIVER_DIR = /home/gnuplot/build/src. During the installation, something went wrong. I want to remove the GNUPLOT_DRIVER_DIR environment variable. How can I achieve it?
A. K.
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18 answers

How can I symlink a file in Linux?

I want to make a symbolic link in Linux. I have written this Bash command where the first path is the folder I want link into and the second path is the compiled source. ln -s '+basebuild+'/IpDome-kernel/kernel…
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How do I change permissions for a folder and its subfolders/files?

How do I change the permissions of a folder and all its subfolders and files? This only applies to the /opt/lampp/htdocs folder, not its contents: chmod 775 /opt/lampp/htdocs How do I set chmod 755 for all of the /opt/lampp/htdocs folder's current…
Adam Halasz
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19 answers

How do I profile C++ code running on Linux?

How do I find areas of my code that run slowly in a C++ application running on Linux?
Gabriel Isenberg
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27 answers

How do I recursively grep all directories and subdirectories?

How do I recursively grep all directories and subdirectories? find . | xargs grep "texthere" *
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How can I update Node.js and NPM to their latest versions?

I just installed Node.js and NPM (Node Package Manager). I installed NPM for access to additional Node.js modules. After I installed Node.js and NPM, I noticed that neither were the latest versions available. How do I upgrade Node.js, NPM, and my…
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How do I exclude a directory when using `find`?

How do I exclude a specific directory when searching for *.js files using find? find . -name '*.js'
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Looping through the content of a file in Bash

How do I iterate through each line of a text file with Bash? With this script: echo "Start!" for p in (peptides.txt) do echo "${p}" done I get this output on the screen: Start! ./ line 3: syntax error near unexpected token…
Peter Mortensen
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How do I prompt for Yes/No/Cancel input in a Linux shell script?

I want to pause input in a shell script, and prompt the user for choices. The standard Yes, No, or Cancel type question. How do I accomplish this in a typical bash prompt?
Myrddin Emrys
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5 answers

What is ':-!!' in C?

I bumped into this strange macro code in /usr/include/linux/kernel.h: /* Force a compilation error if condition is true, but also produce a result (of value 0 and type size_t), so the expression can be used e.g. in a structure initializer (or…
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How to redirect output to a file and stdout

In bash, calling foo would display any output from that command on the stdout. Calling foo > output would redirect any output from that command to the file specified (in this case 'output'). Is there a way to redirect output to a file and have it…
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Merge / convert multiple PDF files into one PDF

How could I merge / convert multiple PDF files into one large PDF file? I tried the following, but the content of the target file was not as expected: convert file1.pdf file2.pdf merged.pdf I need a very simple/basic command line (CLI) solution.…
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