CentOS is a super solid Linux distro. However, its default repository’s packages are limited compared to Fedora. Even Fedora needs some additional repositories to have software packages for daily usage, such as MPlayer, ffmpeg. Fortunately, some community maintained repositories provides these software. In this post, we introduce theses additional common repositories and how to install…
Many Linux distros, such as RHEL/CentOS 7, Fedora, Ubuntu 16, are now using systemd instead of init as the init system. It is common for Linux users to set Linux to boot to “GUI” or “Text” mode. The old way of changing ‘/etc/inittab’ for choosing Linux runlevels is not working for sytemd. This post will…
In this post, asp.net development India based professionals will brief you about the interesting feature of AngularJS, that I Routing. You will learn the method to split the single page into multiple views. For more info, read the article. In this article we are going to see one of the most useful feature of AngularJS…
In this post, java development India based experts will explain the concept of Quartz. You will also learn the method of setting up the Quartz in this article. You can ask experts if anything bothers you. Technology Quartz is the open source Java technology for scheduling background jobs. If we want to execute the task…
People are sometimes given access to Linux/Unix and asked to change their initial passwords. But for beginners, changing a Linux/Unix password is not an easy task, especially when there is only SSH log on allowed to the Linux/Unix server. This post introduces how to change password of user USER on host HOST remotely using SSH….
Linux may report “device is busy” when we try to umount a filesystem. This behavior is reasonable as it can help us avoid data loss by disallowing unmouting a filesystem when it is being used. But for situations when we are sure there is something wrong happened or we care not data lost such as…
Attaching a USB keyboard to a laptop is common when using a laptop because a normal keyboard may provide a more convenient typing experience. The laptop keyboard is not used in these situations. However, the laptop keyboard may still be touched by accident. In this post, we will discuss how to disable and enable the…
Junk Emails, or Email spams, are annoying and they cost time to deal with. While they are something we need to cope with, we can use tools to help us. Thunderbird has an adaptive junk filter that can learn from user’s actions to identify junk messages. I find that Thunderbird default settings are not fully…
Bash script may need to get its own path. In normal Bash script, $0 is the path to the script. However, when a script is sourced, such as . a.sh, a.sh‘s $0 does not give a.sh while the caller’s name. How to reliably get a bash script’s own path no matter whether the Bash script…
How to set the static IP address for CentOS 7/Fedora 22+ is introduced in this post. Here, we assume the Linux is using NetworkManager to manage the network. All steps are done as root. Find the interface you want to set the address Command ifconfig -a lists all interfaces. Find the interface name to set,…
It is common to execute commands on many nodes/hosts via SSH for managing a cluster of Linux servers. On Linux, there are many choices for this task. Generally, to run commands on many nodes, there are two modes: serial mode and parallel mode. In serial mode, the command is executed on the node one by…
In Firefox on Linux Mint, Google is not in the default list of search engines. Linux Mint has its criteria for adding search engines while Google seems not in those suggested by Linux Mint because “Amongst commercial search engines, only the ones which share with Linux Mint the revenue Linux Mint users generate for them…
Linux is a great platform for software development targeting servers or backends. In general, working on Linux is very productive. The problem that beginners on Linux face is the the learning curve is steep at the beginning. But believe me, after you get through the initial green steep learning step as in the figure below…
Amazon S3 is a widely used public cloud storage system. S3 allows an object/file to be up to 5TB which is enough for most applications. The AWS Management Console provides a Web-based interface for users to upload and manage files in S3 buckets. However, uploading a large files that is 100s of GB is not…
After the post Fetching RSS Feed and Outputing Feed Items as HTML in PHP was originally published, there are some updates such as adding a simple RSS feed caching mechanism and supporting scanning content parts of the feed items for images. Recently, Webucator makes a great tutorial video on introducing the RSS to HTML PHP…
PowerPoint uses 96 dots per inch (dpi) by default when you export a slide. The DPI of the images like .tif ones exported from PowerPoint are always 96. In the options of PowerPoint, there is a setting for choosing DPIs. However, it have no effect. For some needs like images for printing posters, larger DPIs…
As you may know, Adobe stopped supporting the NPAPI version of Flash on Linux and the latest NPAPI version of Flash player at version 11.2 released back in 2012 will only receive security fixes. Even the security fixes to the 11.2 version of the Flash Plugin your Firefox is using will end on May 4,…
SSH is a very common tool for Linux/Unix platforms. One annoying problem when using SSH is that the connection may get disconnected if the SSH connection is idle for some time under common configurations. Users may run an infinite loop like while true; do uptime; sleep 30; done when there is no work to be…
It is common practice to calculate the checksums for files to check its integrity. For large files, the checksum computation is slow. Now I am wondering why it is so slow and whether choosing another tool will be better. In this post, I try three common tools md5sum, sha1sum and crc32 to compute checksums on…
Doing actions upon changes of files and directories is very useful. Examples like compiling a project after the source code files are changed, sending emails after important configuration files are modified, building the PDF after a TeX file is modified. On Linux, the inotify-tools provide good support for trigger actions after changes. In this post,…