Unix-an Overview

INTRODUCTION OF UNIX

WHAT IS UNIX

• It's a family of operating systems - MacOS , Android , iOS , Linux etc.
• Windows is one of the main operating systems that doesn’t belong to unix OS family .

• As a developer you will need to learn some basic Unix commands to do variety of opertions.

  Unix OS

  shell

• The shell is the interface between the user and the kernel.

• It accepts and interprets commands through a command line interface (CLI) , also called terminal.
• There are many types of shell -
  • BASH - Bourne again shell.
  • C shell etc.

USES OF UNIX

• Multi-tasking. Unix is designed for high-performance computing. ...
• A backbone of modern technologies. ...
• Impactful towards other OS. ...
• An invention of Linux. ...
• A host of services. ...
• Command-line functionality. ...
• Text-based processes. ...
• Regular Expression.

HISTORY

• The history of Unix dates back to the mid-1960s when the Massachusetts Institute of Technology, AT&T Bell Labs, and General Electric were jointly developing an experimental time-sharing operating system called Multics for the GE-645 mainframe. Multics introduced many innovations, but had many problems. -Default; user interface: Command-line interface & Graphical (X Window System).

  -Developers : Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna at Bell Labs.

  -Initial release: 1969; 52 years ago.

  -License: Proprietary.

  -OS family : Unix.

  -Source model: Historically closed source, now some Unix projects (BSD family and Illumos) are open sourced.

  -Written in: C and Assembly language.

IMPORTANT UNIX COMMANDS

• echo (text): To print text on the terminal screen.

• clear: To clear the terminal screen.
• exit: To exit the terminal.
• pwd: Present working directory.
• ls: it list all the stuff inside this particular directory.
• cd: change directory means to enter the child directory from a parent directory.
• cd ..: To go back in parent directory i.e . a step back.
• man: used to display manual for any command.
• ls -l: It shows a list of stuff along with all information such as file permission information , file, size, date and time it was created , number of files inside it, and name of the files.
• ls -a: It also shows a list similar to "ls -l" command but it also show the hidden files.
• ls -s: To display a list of stuff sorted by the size.
• ls -r: To display a list of stuff in reverse order.
• touch: To create a new file.
• echo "text" >> file.txt: To update a line in the file.
• head (file.txt): To show the top 10 line of the file.
• tail (file.txt): To show the bottom 10 line of the file.
• cat (file.txt): To display the file on the terminal screen.
• nano (file.txt): To open the editor window for the file.
• grep: To find the string in the file.
• grep -n: To find the sting along with the line number in the file.
• mkdir: To make a new directory.
• rm: used to delete the file.
• rmdir: used to delete the empty directory.
• rm -r: To delete any folder.
• mv (old name) (new name): used to rename the folder.
• cp (source) (destination): to copy the file.

IMPORTANT SHORTCUT KEY

• Ctrl+C : copy text.
• Ctrl+V : paste text.
• Ctrl+X : cut text.
• Ctrl+Z : undo.
• Ctrl+Alt+T : open terminal.
• Ctrl+Alt+D : show desktop.
• Alt+Tab : switch Tab.
• Ctrl+W : close window.
• Ctrl+X : exit from editor window.
• Ctrl+Z : To come out of any command in terminal.
• Ctrl+C : To came out of any command in terminal.
• Ctrl+Shift+C : copy from terminal.
• Ctrl+Shift+V : paste in terminal.