UNIX Journey Workshop:

Table of Content:

• 1. What is UNIX?
• 2. History of UNIX?
• 3. UNIX Architecture
  • 3.1 Kernel
  • 3.2 shell
  • 3.3 Programs
• 4. Why use UNIX?
• 5. UNIX File system
  • 5.1 Quick notes
  • 5.2 The File system Hierarchy
• 6. Basic commands
  • 6.1 Command Structure
  • 6.2 Common commands
• 7. process
  • 7.1 what is a process?
  • 7.2 what processes are running?
  • 7.3 multitasking
  • 7.4 kill process
  • 7.5 top
• 8. Jobs
• 9. Packages
  • 9.1 compression
  • 9.2 install Packages
• 10. cut

to be added:

• sort
• unique
• permissions
• head/tail
• vim text manipulation

1. What is UNIX?

• Unix is on of the first widely-used operating systems.

• Is the basis for many modern Operating systems.

• Helped set a standard for the multi-tasking multi-user systems

2. History of UNIX

• 1969 Ken Thompson, Dennis Ritchie start working on a file system, and name their system UNICS, which is later changed to UNIX.

• 1973 Thompson and Ritchie rewrote UNIX in C (while most of the operating systems at that time were written in assembly)

• 1991 Linux, GNU, and others: similar to UNIX, but their source code rewritten, very popular and widespread, free. _{(Many Linux Distributions: Ubuntu, Fedora, Debian, ...)}

3. UNIX Architecture

3.1 Kernel:

The part manages and controls the machine and takes care of scheduling of various computer Programs

3.2 Shell:

A command interpreter that looks after the communication between the user and the system.

3.1 Programs:

various utility Programs which performs a number of tasks (editing a file, sorting numbers or drawing a plot, .....)

4. Why use UNIX?

• Allows you to accomplish and automate complicated tasks that would usually require huge manual labor.

• A rich set of small commands and utilities that can be combined in unlimited ways to perform complex custom tasks.

• It is fun!

• Not limited to pre-configured combinations or menus, as in personal computer systems.

• Extremely useful computer skill that will be relevant many years from now.

5. UNIX File system

5.1 Quick notes:

• the unix file system consists of one single global root directory that encapsulates everything of the machine. no matter how many disks or volumes are there.

• Files and directories names are case sensitive.

• The way to separate directories is with a forward slash "/".

5.2 The File system Hierarchy:

• Root : Main & parent Directory

• /home: contains all the users and the user data and files

• /dev : Access to hardware devices

• /lib : Stores the libraries

• /mnt : is used to mount disk drives

• /usr : user installed Programs and files

• /etc : system Settings

6. Basic commands:

6.1 Command Structure:

Command [opt1] [opt2]

6.2 Common commands:

• print working directory (pwd):

  • Prints the full path of the current directory

  • Very handy when you get lost in the directories jungle

  • A useful variable for the strings

• list (ls) [flags] <file> :

• Lists the content of the current directory.

common options:

' - l ' => List a detailed file/folder information.

' - lh ' => List a detailed file/folder information.

' - a ' => list hidden files.

' - ls ' => sort files by size.

• change directory (cd) <directory name>:

  • goes from the current directory to the specified one.

  • defaults to the home directory if not given a destination.

  • can take both absolute or relative paths.

  relative: the location of a file or a folder that beginning at the current directory.

  cd csc1101

  absolute: the location of a file or a folder starting at _{(home directory)}

  cd /home/user1/csc1101

  shortcuts:

  ' ~ ' => Current user's home directory.

  ' . ' => The current directory.

  ' .. ' => The parent of the current directory.

  ' - ' => The previous directory.

• Make a file (touch) [flag] <file>:

  • creates a new file with the name
  • Adjusts the timestamp of

• Make Directory (mkdir) [flags] <directory> :

  • makes a new directory with the name

  • can use relative and absolute paths to make directories outside the current directory.

  common options:

  ' - p ' => creates parent folders as well.

• Remove File (rm) [flags] <file>

  • removes the file called
  • Using wildcards you can remove multiple files.

  common options:

  ' - i ' => prompt before removal.

  ' - f ' => force remove.

  ' - r ' => recursively remove all files in a directory.

• Remove Directory (rmdir) [flags] <directory>

  • removes an empty directory <directory>.
  • Throws error if the directory is not empty.

  common options:

  ' - p ' => removes folder and its ancestors.

• Copy (cp) [flags] <file> <destination>

  • copies from location to <destination>

  • to copy multiple files you can use wildcards (such as * )

• Move (mv) [flags] <file> <destination>

  • Moves a file or directory from one place to another

  • Also used for renaming, just move from <oldname> to <newname>

• File type (file) <file>

  • will show you a description of the file’s contents.

• Find File (find) <starting point> <type> <name>

  • looks through any sub-directory to find a file

• Locate File (locate) [flag] <name>

  • similar to find
  • no need to specify a starting directory (it searches the system)

  common options:

  ' - n ' => limit the result to 20 entries.

  ' - c ' => count the number of results.

• current user (whoami)

  • prints the name of the current user.

• (which)

  • used to locate the executable file associated with the given command.

7. Process

7.1 What is a process?

• An instance of a running program.

• More specific than a program

• Each process is given a unique id (PID)

7.2 What processes are running now?

• process screenshot (ps) [flags]

  • Reports a snapshot of the current running processes, including PIDs
  • Lists the processes created by the user in the current terminal

  common options:

  ' - e ' => every process currently running.

  ' - u user' => processes created by this user.

7.3 Multitasking

• Quick switching back and forth between processes makes it seem as though they are all running simultaneously.

• Each process has a priority that can be set and changed by the user.

• priorities range from -20(highest) to 19(lowest), if process is started with out a priority defaults to 0

• nice process (nice) [flags] <command>

  • starts a process with the set priority.

  • if priority is not set default is 10

  • only root user can set priority below 0

  common options:

  ' - n ' => priority.

• renice process (renice) [flags] <PID>

  • changes the priority of a running process.

  • can change the processes created by this user only

  • only root user can set priority below 0

  common options:

  ' - n ' => priority.

7.4 Kill processes

• kill process (kill) <PID>

  • Kills the process with this ID.

• kill all processes (killall) [flag] <Process name>

  • Kills all the processes of the current program.

  common options:

  ' - TERM ' => Terminates execution (default).

  ' - HUP ' => Hang-up (restarts the program).

  ' - KILL ' => Like bleach, can kill anything.

7.5 TOP

• running processes (top)
  • All in one stop for process management

common options:

' h ' => Help menu. ' Z ' => Set colors. ' k/K ' => Kill a Process. ' r ' => renice.

8. Jobs

• Check jobs (jobs)

• Prints the current jobs with details and job id.

• resume job (bg) <ID>

  • Restart a stopped background process.

• foreground (fg) <ID>

  • Bring a background process to the foreground.

• kill job (kill) %<ID>

  • kills the job with the given id.

9. Packages

9.1 Compression

• compress file (gzip) <file>

  • can compress a single file.
  • doesn't create a new compressed file
  • compresses the file into a ".gz" archive.

• decompress file (gunzip) <file>

  • decompresses the file.

• compress file (tar) cvf <file name> <source file>

  • compress as full directories.

  • creates a new copy that is compressed.

  • compresses the file into a ".tar" archive.

  • "c" => create

  • "v" => verbose / show progress

  • "f" => file name

• decompress file (tar) xvf <file>

  • decompresses the file.

  • "x" => extract

  • "v" => verbose / show progress

  • "f" => file name

9.2 install packages

• Debian package management (apt) [option]

  • manages the packages on the device.

  options:

  • "install" => installs a package
  • "remove" => removes a package
  • "show" => shows the details of a package

10. cut:

• Cut on delimiter__(cut) [flag] __

  • returns parth of the text.

    options:

    • "c" => returns character
    • "f" => returns a field
    • "d" => change the delimiter to break on