Introduction to Linux PDF

Introduction to Linux Dr. G Suresh Kumar What is Linux? Linux is a Unix clone written from scratch by Linus Torvalds with assistance from a team of hackers across the Net. Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T empl...

Introduction to Linux Dr. G Suresh Kumar What is Linux? Linux is a Unix clone written from scratch by Linus Torvalds with assistance from a team of hackers across the Net. Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs. Linux and Unix strive to be POSIX compliant. 64% of the world’s servers run some variant of Unix or Linux. The Android phone and the Kindle run Linux. What is Linux? “Small programs that do one thing well” (see unix-reference.pdf) Network: ssh, scp, ping, telnet, nslookup, wget Shells: BASH, TCSH, alias, watch, clear, history, chsh, echo, set, setenv, xargs System Information: w, whoami, man, info, which, free, echo, date, cal, df, free, man, info Command Information: man, info Symbols: |, >, >>, &, 2>&1, ;, ~,.,.., $!, !:, ! Filters: grep, egrep, more, less, head, tail Hotkeys: , File System: ls, mkdir, cd, pwd, mv, ln, touch, cat, file, find, diff, cmp, /net//, mount, du, df, chmod, find Line Editors: awk, sed File Editors: vim, gvim, emacs –nw, emacs User manual: man command Linux Command-Line Interface Linux shells: A shell is a command interpreter that allows you to type commands from the keyboard to interact with the operating system kernel. sh (Bourne Shell) The sh shell was the earliest shell, being developed for UNIX back in the late 1970s. bash (Bourne-Again Shell) The bash shell is an improved version of the sh shell and is one of the most popular shells today. It’s the default shell used by most Linux distributions. csh (C Shell) The csh shell was originally developed for BSD UNIX. It uses a syntax that is very similar to C programming. tsch The tsch shell is an improved version of the C Shell. It is the default shell used on FreeBSD systems. zsh (Z Shell) The Z Shell is an improved version of the bash shell. 9