An alias is nothing but shortcut to commands. The alias command allows user to launch any command or group of commands (including options and filenames) by entering a single word. Use alias command to display list of all defined aliases. You can add user defined aliases to ~/.bashrc file. You can cut down typing time with these aliases, work smartly, and increase productivity at the command prompt.
In Linux and UNIX system services are configured using various text files located in /etc/ or /usr/local/etc/ directory tree. A typical server system could have dozens of configuration files.You can check your configuration files for syntax errors without starting the server and validate all settings. In some cases, it is possible to to check the sanity of the specific data (such as keys) or directories (such as /var/lib/cache/). Text files are easier to manage remotely. You can use ssh and a text editor. If there is an error in configuration, the server may not start. It may result in a disaster. This post explains how to quickly find out a syntax error for popular servers and test configuration file for syntax errors.
Man pages are written by sys-admin and developers for IT techs, and are intended more as a reference than as a how to. Man pages are very useful for people who are already familiar with Linux, Unix, and BSD operating systems. Use man pages when you just need to know the syntax for particular commands or configuration file, but they are not helpful for new Linux users. Man pages are not good for learning something new for the first time. Here are thirty best documentation sites on the web for learning Linux and Unix like operating systems.
Unhide is a little handy forensic tool to find hidden processes and TCP/UDP ports by rootkits / LKMs or by another hidden technique. This tools works under both Linux / Unix, and MS-Windows operating systems. From the man page:
It detects hidden processes using three techniques:
- The proc technique consists of comparing /proc with the output of /bin/ps.
- The sys technique consists of comparing information gathered from /bin/ps with information gathered from system calls.
- The brute technique consists of bruteforcing the all process IDs. This technique is only available on Linux 2.6 kernels.
PHP is an open-source server-side scripting language, and it is a widely used. The Apache/Nginx/Lighttpd web server provides access to files and content via the HTTP OR HTTPS protocol. A misconfigured server-side scripting language can create all sorts of problems. So, PHP should be used with caution. Here are twenty-five php security best practices for sysadmins for configuring PHP securely.
You can now enjoy mysteries of the sea from the safety of your own terminal using ASCIIQuarium. It is an aquarium/sea animation in ASCII art created using perl.
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.
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.
Nginx is a lightweight, high-performance web server/reverse proxy and e-mail (IMAP/POP3) proxy. It runs on UNIX, GNU/Linux, BSD variants, Mac OS X, Solaris, and Microsoft Windows. According to Netcraft, 13.50% of all domains on the Internet use nginx web server. Nginx is one of a handful of servers written to address the C10K problem. Unlike traditional servers, Nginx doesn’t rely on threads to handle requests. Instead, it uses a much more scalable event-driven (asynchronous) architecture. Nginx powers several high traffic web sites, such as WordPress, Hulu, Github, and SourceForge.