KTU FOSS LAB - Dr Binu V P

Basic Features Following are some of the important features of Linux Operating System. Portable  − Portability means software can works on different types of hardware in same way. Linux kernel and application programs supports their installation on any kind of hardware platform. Open Source  − Linux source code is freely available and it is community based development project. Multiple teams work in collaboration to enhance the capability of Linux operating system and it is continuously evolving. Multi-User  − Linux is a multiuser system means multiple users can access system resources like memory/ ram/ application programs at same time. Multiprogramming  − Linux is a multiprogramming system means multiple applications can run at same time. Hierarchical File System  − Linux provides a standard file structure in which system files/ user files are arranged. Shell  − Linux provides a special interpreter program which can be used to execut...

Perl is a programming language developed by Larry Wall, especially designed for text processing. Though Perl is not officially an acronym but many times it is used as it stands for Practical Extraction and Report Language . It runs on a variety of platforms, such as Windows, Mac OS, and the various versions of UNIX. The language is intended to be practical (easy to use, efficient,complete) rather than beautiful (tiny, elegant, minimal).It combines (in the author's opinion, anyway) some of the best features of sed, awk, and sh, making it familiar and easy to use for Unix users to whip up quick solutions to annoying problems.  Its general-purpose programming facilities support procedural, functional, and object-oriented programming paradigms, making Perl a comfortable language for the long haul on major projects, whatever your bent. Perl's roots in text processing haven't been forgotten over the years.It still boasts some of the most powerful regular expressions to be ...

AWK is a programming language designed for text processing and typically used as a data extraction and reporting tool. It is a standard feature of most Unix-like operating systems. The AWK language is a data-drivenscripting language consisting of a set of actions to be taken against streams of textual data – either run directly on files or used as part of a pipeline – for purposes of extracting or transforming text, such as producing formatted reports. The language extensively uses the stringdatatype, associative arrays (that is, arrays indexed by key strings), and regular expressions. While AWK has a limited intended application domain and was especially designed to support one-liner programs, the language is Turing-complete, and even the early Bell Labs users of AWK often wrote well-structured large AWK programs. AWK was created at Bell Labs in the 1970s,and its name is derived from the surnames of its authors—Alfred Aho, Peter Weinberger, and Brian Kernighan. Learn more on...

You can connect two commands together so that the output from one program becomes the input of the next program. Two or more commands connected in this way form a pipe. To make a pipe, put a vertical bar (|) on the command line between two commands. When a program takes its input from another program, it performs some operation on that input, and writes the result to the standard output. It is referred to as a filter. The following are some of the filter commands . Click the commands to see the man page and learn different options. wc - count number of lines words and characters cut - cut the files vertically character or field wise paste - vertically paste two files head - get lines from the beginning of a file tail -get lines from the end of a file sort - sort the files contents grep , egrep , fgrep - search file contents uniq - unique lines from a sorted file join - joining two files tr - translating characters awk -is a full-featured text processing language   ...

“Free software” means software that respects users' freedom and community. Roughly, it means that the users have the freedom to run, copy, distribute, study, change and improve the software. Thus, “free software” is a matter of liberty, not price. To understand the concept, you should think of “free” as in “free speech,” not as in “free beer”. We sometimes call it “libre software,” borrowing the French or Spanish word for “free” as in freedom, to show we do not mean the software is gratis. The four essential freedoms A program is free software if the program's users have the four essential freedoms:  The freedom to run the program as you wish, for any purpose (freedom 0). T he freedom to study how the program works, and change it so it does your computing as you wish (freedom 1). Access to the source code is a precondition for this. The freedom to redistribute copies so you can help your neighbour (freedom 2). The freedom to distribute copies of your modified versions to ...

1991: The Linux kernel is publicly announced on 25 August by the 21-year-old Finnish student Linus Benedict Torvalds. 1992: The Linux kernel is relicensed under the GNU GPL. The first Linux distributions are created. 1993: Over 100 developers work on the Linux kernel. With their assistance the kernel is adapted to the GNU environment, which creates a large spectrum of application types for Linux. The oldest currently (as of 2015) existing Linux distribution, Slackware , is released for the first time. Later in the same year, the Debian project is established. Today it is the largest community distribution. 1994: Torvalds judges all components of the kernel to be fully matured: he releases version 1.0 of Linux. The XFree86 project contributes a graphical user interface (GUI). Commercial Linux distribution makers Red Hat and SUSE publish version 1.0 of their Linux distributions. 1995: Linux is ported to the DEC Alpha and to the Sun SPARC. Over the following years it is ported to an ev...

alias aliasname='command' creates a temporary macro aliasname that executes command chsh changes the shell clear clears the screen crontab maintain crontab files for individual users env < VARIABLE=value> sets environmental VARIABLE to value (blank to show all) kill pid kills process pid . kill –9 pid to force kill (use ps to list pid) newgrp group sets group as the primary group owner for new files created nice -n priority command executes the command with a specified priority renice priority pid changes a program's priority level afterwards (see nice , ps ). script logs everything that you type to . “exit” to quit. sleep time makes the computer wait for time . Try “sleep 30; echo Go” telinit level specifies which runlevel to run at (0 = halt, 1 = single-user, 3 = full multi-user, 5 = X-windows, 6 = reboot) umask permission changes the default file permission for new files (ex: rw-r—r--). umask 077 makes all new files rw------. The pe...