The $ character is used for parameter expansion, and command substitution. You can use it for manipulating and expanding variables on demands without using external commands such as sed or awk.
I recently brought Canon EOS 500D mid-range DSLR cameras with good promotional discounts. My photography interests date back to my school days but I did not take photography seriously until recently. Now, I’m researching for quality open source photo-software which may be available to photographers. This blog post gives a quick and dirty view of the different photo applications available for Linux operating systems:
Server provisioning is nothing but load the Linux or UNIX like operating systems automatically with actual operating systems, device drivers, data, and make a server ready for network operation without any user input. Typically you select a server from a pool of available servers, load the operating systems (such as RHEL, Fedora, FreeBSD, Debian), and finally customize storage, network (IP, gateway, bounding etc), drivers, applications, users etc. Using the following tools you can perform automated unattended operating system installation, configuration, set virtual machines and much more. These software can be used to install a lot (say thousands) of Linux and UNIX systems at the same time.
A few years ago Novell conducted an online public survey to determine which MS-Windows apps need to be ported on Linux desktop. Adobe Photoshop and other graphics application that user want ported to Linux. However, Linux comes with the sheer numbers of open source software projects produced by the community. You may overwhelmed by the choices available under Linux and not know where to begin.
A regular question from my mailbag:
I am in the process of up grading my computer. Where can I get a list of the WUSB for Linux?
Wireless USB adapters are pretty popular for desktop and laptop usage in home. It is capable of sending 480 Mbit/s at distances up to 3 meters and 110 Mbit/s at up to 10 meters. Newer N series can work at 270Mbit/s at up to 300 meters. However, 50-100 meters are acceptable ranges. Unfortunately, finding Linux compatible USB wireless adapter is a big challenge due to driver issues. Over a past few years, I’ve used and installed various USB wireless adapters and created my own small HCL for it. In this quick blog post I will list all working USB wireless adapter.
It is no secret that I am a pretty big fan of excellent Linux Software RAID. Creating, assembling and rebuilding small array is fine. But, things started to get nasty when you try to rebuild or re-sync large size array. You may get frustrated when you see it is going to take 22 hours to rebuild the array. You can always increase the speed of Linux Software RAID 0/1/5/6 reconstruction using the following five tips.
Interesting read and I wasn’t aware of some of the facts behind the open-source entrepreneur Bob Young. From the BBC article:
Bob Young is a self-confessed contrarian with a strong desire to change the world by allowing people to share and collaborate. The approach has served him well and has helped turn the Canadian into a multi-millionaire. Bob YoungFrom the outset, his software company Red Hat bucked the trend set by the big players like Microsoft which stubbornly guarded every line of code and charged whopping fees to maintain it.
Core dumps are often used to diagnose or debug errors in Linux or UNIX programs. Core dumps can serve as useful debugging aids for sys admins to find out why Application like Lighttpd, Apache, PHP-CGI or any other program crashed. Many vendors and open source project author requests a core file to troubleshoot a program. A core file is generated when an application program abnormally terminates due to bug, operating system security protection schema, or program simply try to write beyond the area of memory it has allocated, and so on. This article explains how to turn on core file support and track down bugs in programs.
There are some misconceptions that shell scripts are only for a CLI environment. You can easily use various tools to write GUI and/or network (socket) scripts under KDE or Gnome desktops. Shell scripts can make use of some of the GUI widget (menus, warning boxs, progress bars etc). You can always control the final output, cursor position on screen, various output effects, and so on. With the following tools you can build powerful, interactive, user friendly UNIX / Linux bash shell scripts.
Generally, all Linux distributions needs a scheduled reboot once to stay up to date with important kernel security updates. RHN (or other distro vendors) provides Linux kernel security updates. You can apply kernel updates using yum command or apt-get command line options. After each upgrade you need to reboot the server. Ksplice service allows you to skip reboot step and apply hotfixes to kernel without rebooting the server. In this post, I will cover a quick installation of Ksplice for RHEL 5.x and try to find out if service is worth every penny.