Introduction

What is Unix?

• Unix, Linux, *nix, …. : What is it?
• Operating System
• Created in 1969 in the Bell Labs
• Multi-user
• Multi-task
• Protected memory
• Unix family: BSD, Linux, Mac OS X (Darwin), Android, etc.

Why use Unix on the computing servers of the Institut Pasteur?

• Fares well in the scientific domain
• Multi-user
• Versatile
• Powerful

What is the Unix shell?

• a shell is a user interface for access to an operating system's services.
• a shell can be a command line interface or a graphical user interface
• in a command line interface, the user issues commands to the program in the form of successive lines of text (command lines).
• what is commonly referred as "Unix shell" is a set of commonly-used CLI programs.

Commands

• A command is an instruction you send to the shell to ask it to execute an action.

Syntax: command, options, arguments

• the command: what action should be executed

• the arguments: the object of the action

• the options: flags that specify or modify the behaviour of the command

  • options are usually preceded by

    • - if its a one letter option
    • -- if its a word option

    command <options> <aguments>
    
    ls -a
    ls --all