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Stack Overflow

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 https://unix.stackexchange.com or the specific Linux distribution's Stack Exchange site like https://askubuntu.com or https://elementaryos.stackexchange.com/

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 .

Design

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
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3 answers

How do I create a copy of a directory in Unix/Linux?

I want to recursively create a copy of a directory and all its contents (e.g. files and subdirectories).
user2080656
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3 answers

How can I use grep to show just filenames on Linux?

How can I use grep to show just file-names (no in-line matches) on Linux? I am usually using something like: find . -iname "*php" -exec grep -H myString {} \; How can I just get the file-names (with paths), but without the matches? Do I have to use…
cwd
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34 answers

How to kill a process running on particular port in Linux?

I tried to close the tomcat using ./shutdown.sh from tomcat /bin directory. But found that the server was not closed properly. And thus I was unable to restartMy tomcat is running on port 8080. I want to kill the tomcat process running on 8080. I…
veer7
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1388
votes
28 answers

How to count lines in a document?

I have lines like these, and I want to know how many lines I actually have... 09:16:39 AM all 2.00 0.00 4.00 0.00 0.00 0.00 0.00 0.00 94.00 09:16:40 AM all 5.00 0.00 0.00 4.00 0.00 0.00 0.00 0.00 …
Alucard
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1342
votes
13 answers

UTF-8 all the way through

I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1. Where exactly do I need to set the encoding/charsets?…
mercutio
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1309
votes
21 answers

Which version of PostgreSQL am I running?

I'm in a corporate environment (running Debian Linux) and didn't install it myself. I access the databases using Navicat or phpPgAdmin (if that helps). I also don't have shell access to the server running the database.
Highly Irregular
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32 answers

Pipe to/from the clipboard in a Bash script

Is it possible to pipe to/from the clipboard in Bash? Whether it is piping to/from a device handle or using an auxiliary application, I can't find anything. For example, if /dev/clip was a device linking to the clipboard we could do: cat /dev/clip …
moinudin
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1209
votes
15 answers

Defining a variable with or without export

What is export for? What is the difference between: export name=value and name=value
flybywire
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1191
votes
12 answers

Remove a symlink to a directory

I have a symlink to an important directory. I want to get rid of that symlink, while keeping the directory behind it. I tried rm and get back rm: cannot remove 'foo'. I tried rmdir and got back rmdir: failed to remove 'foo': Directory not empty I…
Matthew Scouten
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1163
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29 answers

Using ls to list directories and their total sizes

Is it possible to use ls in Unix to list the total size of a sub-directory and all its contents as opposed to the usual 4K that (I assume) is just the directory file itself? total 12K drwxrwxr-x 6 *** *** 4.0K 2009-06-19 10:10 branches drwxrwxr-x…
kmorris511
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1105
votes
5 answers

Why does the C preprocessor interpret the word "linux" as the constant "1"?

Why does the C preprocessor in GCC interpret the word linux (small letters) as the constant 1? test.c: #include int main(void) { int linux = 5; return 0; } Result of $ gcc -E test.c (stop after the preprocessing…
ahmedaly50
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1103
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15 answers

How do I use sudo to redirect output to a location I don't have permission to write to?

I've been given sudo access on one of our development RedHat linux boxes, and I seem to find myself quite often needing to redirect output to a location I don't normally have write access to. The trouble is, this contrived example doesn't work: sudo…
Jonathan
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1090
votes
10 answers

What does set -e mean in a bash script?

I'm studying the content of this preinst file that the script executes before that package is unpacked from its Debian archive (.deb) file. The script has the following code: #!/bin/bash set -e # Automatically added by dh_installinit if [ "$1" =…
AndreaNobili
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1085
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14 answers

How can I exclude directories from grep -R?

I want to traverse all subdirectories, except the node_modules directory.
TIMEX
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1075
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30 answers

Shell command to tar directory excluding certain files/folders

Is there a simple shell command/script that supports excluding certain files/folders from being archived? I have a directory that need to be archived with a sub directory that has a number of very large files I do not need to backup. Not quite…
deepwell
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