What is an OS?

  • DOS, Windows, Linux, Mac OS, iOS, Android, ...


  • OS
  • Made by Linus Torvalds
  • Inspired by Unix
  • Debian, CentOS, Ubuntu, Fedora, Redhat Linux, Gentoo, Arch, Suse, Slackware, Mandriva, PintOS, ...

Why Linux?

  • Custom
  • Free (in some sense)
  • Open source
  • Supports multiple users
  • Has compatibility with Unix-like OSs



  • .: current directory
  • ..: parent directory
  • ~/: home directory
  • /: root directory
  • /some/absolute/path
  • some/relative/path


  • Read, Write, eXecute
  • Owner, Owner group, Others
  • rwxrwxrwx
    • All permissions for everyone

What is Bash?

  • Bash is a "shell" for the GNU operating system

Then what is a shell?

  • A shell is a macro processor that executes commands

Is Bash the only shell available?

  • No.
  • There are many many alternatives, such as sh, ksh, csh or zsh
  • However, bash is the default shell in GNU systems

Can I use bash in GNU systems only?

  • No.
  • You can also use bash in Windows and other platforms, using portable versions

Why should I use Bash?

Package managing

  • What is a package?
  • What is it to manage a package?
  • What kind of package managers are there?

    • Windows: ???
    • Mac: Homebrew
    • Ubuntu: apt-get

Data science