Linux is a family of open-source Unix-like operating systems based on the Linux kernel.
The Linux kernel is an operating system kernel first released on September 17, 1991, by Linus Torvalds.
Linux is typically packaged in a Linux distribution. Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Popular Linux distributions include Debian, Fedora, and Ubuntu. Commercial distributions include Red Hat Enterprise Linux and SUSE Linux Enterprise Server. Desktop Linux distributions include a windowing system such as X11 or Wayland, and a desktop environment such as GNOME or KDE Plasma. Distributions intended for servers may omit graphics altogether, or include a solution stack such as LAMP. Because Linux is freely redistributable, anyone may create a distribution for any purpose.
I begin to use vim for programming. I like the tools that focus on one function. I used to use emacs. But I think I like vim more. For debugging, I use gdb. But I use the front end cgdb. I can see the codes with the cursor when debugging. I can use F8 for…
“The C language provides no built-in facilities for performing such common operations as input/output, memory management, string manipulation, and the like. Instead, these facilities are defined in a standard library, which you compile and link with your programs. The GNU C library, described in this document, defines all of the library functions that are specified…
Vim provides some basic formatting commands. A combination of these commands with the editing commands will make the programmer happy. A list of basic text formatting commands in Vim: = is an operator that formats/indents text. i{ is a text object that specifies the surrounding code block. It should be used together with v, =,…
When debugging and optimizing programs, developers sometimes need to generate and investigate into the assembly generated by the compiler. Generating a mixed source and assembly list will help a lot for debugging and optimization. gcc can achieve this by working with the assembler. Generate assembly list mixed with the source code Just add these gcc…
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We introduce the method to use DVD as the package repository for yum. In this post, we use CentOS 5 as the example. 1) Modify /etc/yum.repos.d/CentOS-Base.repo Delete baseurls in [Base] baseurl by add ‘#’ at the beginning of the lines Then add a line at the end: baseurl=file:///media/CentOS_5.0_Final ‘file://’ means this is a local directory….
I frequently run some commands/scripts on a batch of servers whose IPs are already collected in a file. I usually use a simple loop and call the ssh to run these commands remotely and automatically. This operation, however, is common and can be abstracted into a separate script. Here is the script that I come…
With a list of servers, it is common that one or more are down or crash. Lots cluster management tools can detect the aliveness of servers. However, it can be easily done with ping with a Bash script. I summarize the script that I used and share it here: check-alive-server.sh. Usage: usage: ./check-alive-server.sh file Each…
With Emacs, I feel happy. I love the rich functions of Emacs, such as compiling, quickly jumping to the lines with compilation error and debugging with gdb, and more. I ever wrote small tips posts about Emacs before. But it is a good idea to put them together and keep adding new ones. Here comes…
QT and GTK applications use different settings for cursor styles. This makes the mouse cursor styles for QT applications in the GNOME / MATE desktop environment or GTK applications in the KDE desktop environment look different with other programs. In the post [[configuring-mouse-cursor-style-for-gtk-applications-in-kde-desktop]], we talked about how to configure the mouse cursor style for GTK…
`diff` and `patch` are tools to create patches and apply patches to source code, which is widely used in the open-source world, such as Linux kernel and application. patch: applying patches To apply a patch to a single file: $ patch < foo.patch If the foo.patch does not identify the file the patch should be...
XPS files is a format from MS on Windows. Evince can view some XPS files, but fails to view some. To view XPS files generated on Windows on a Linux system, we can use mupdf. It works very well. I like it much especially in the situation that Evince fails to open the XPS file….
I ever discussed Starting KDE from Command Line by startx for KDE and GNOME. Recently, I installed MATE desktop on Fedora 17 and am very happy with it—dear, Gnome 2 is back. However, I checked the /etc/X11/xinit/Xclients script which is called by ‘startx’ and it only includes ‘startkde’ and ‘gnome-session’ without support to MATE. But…
An introduction to the general method of installing Domain-U on Xen is introduced here: Setting Up Stable Xen DomU with Fedora: Unmodified Fedora 12 on top of Xenified Fedora 12 Dom0 with Xen (this is a general introduction, some details are changed, such as ‘xl’ replacing ‘xm’, LVM backing the disk for higher performance. But…
iptables is a mechanism in Linux kernel for port forwarding, NAT, firewalls etc. In Linux distros, such as Fedora, the iptables is configured to be as a “strict” firewall that opens a limited know ports, such as 22 for SSH. However, in some network environment, such as a private cluster, the nodes are trusted and…
Fedora Linux starts to use systemd to manage system service. The /etc/inittab is no longer used by systemd. The old method of editing /etc/inittab to change system runlevel does not work anymore. This post introduces a “manual” way to change the boot levels. For the general method, please check https://www.systutorials.com/change-systemd-boot-target-linux/. systemd uses ‘targets’ instead of…
I experienced very slow WiFi network on Linux, while my iPhone seems surf the Internet quit fast. I pinged a site and the RTT is more than 1000ms! There must be something wrong with my Linux configuration. I tried to change the MTU from “Automatic” to “1400” on my Linux box. Surprisingly, it fix the…
Copying some text to a new file is a common operation on Linux. I usually do this by opening the file with ‘vim’, pasting the text in ‘vim’, and then saving the file. I learned a more efficient and quicker way from my advisor during one discussion with him when I show him some results….
The new development of Xen and Linux kernel make it easy to install Xen on Fedora as the Domain-0 now. This post uses Fedora 17 as an example platform to introduce how to set up Domain-0 on Fedora Linux. Compared to our old method (https://www.systutorials.com/setting-up-stable-xen-dom0-with-fedora-xen-3-4-3-with-xenified-linux-kernel-2-6-32-13-in-fedora-12/) which requires manually compiled Xen and patched kernel, the current…
Linux booting is usually controlled by Grub or the new Grub2. Setting the default booting entry is a frequent operations. Here, we introduce how to set the default entry in Grub2 and Grub. Setting the default booting entry in grub2 Note1: With some version of grub2, the grub2-set-default method and the script below may not…