Basic linux commands

• man

• ls

• pwd

• cd

• practice

man

Stands for manual,used to show you the manual of a command

• man

• man ls

  • Navigating the man pages

    "space" Go forword one window.

    "enter" Go forword one line.

    G"b" Go backword one window.

    "/" Search for something in the man.
      Eg./space : search for "space" in man

    "n" Repeat previous search,"next".

    "q" Exit the man page

    
    

  • manls

    This command will not work because "manls" deferent than "man ls"

    
    

  • man 3 ls

    This also will not work because "man 3" used to store C Standard library

    
    

ls

Used to list the content of a directory (files & directories)

• ls

  List the content of the current directory

• ls -l

  Show more details,like permissions & size

• ls -h

  Make the result human readable but not in this case we need to combined it with -l and -s, print sizes like 1K 234M 2G etc.

• ls -l -h ....vs.... ls -lh

  This two commands are the same, because -h & -l can be combined into one option -lh

• ls -lct

  List the content sorted by the last time of modification

• ls -a

  Show the hidden content as well

• ls /etc/

  List the content of /etc directory
    - /etc: contains system configuration

• lsusb

   List informations about USB buses in the system and the devices connected to them. /pre>  
  

• ls --color

    --color=auto : give each file type deferent color
    --color=never : this is the default(show all file types with the same color)

pwd

Print the Working Directory (print the full path of where you are)

cd

Change the Directory (cd PATH)

• cd "or" *cd ~*

  Go to user home directory

• cd /

  Go to root directory

• pwd

  this will print "/" beacause we are in the root directory

• cd ..

  Go back one level up from the current directory

• cd /usr/bin

    Go to /usr/bin directory
    - /usr/bin: contains most of the executable files

• cd -

  Change to the previous working directory & the writes its name

Practice

• Setting up a new user to practice in a clear environment

    $ sudo useradd coco
    $ su - coco

• 10. Return to the User directory, create a new direc tory using the command "mkdir", delete this directory with "rmdir" then return to the root directory.

    $ cd
    $ mkdir myDir
    $ rmdir myDir
    $ cd /

• 11. Create the directory again in the same location without changing the current directory (until further notice).

    $ mkdir ~/myDir

• 12. Create a file with the “touch” command in the user folder.

    $ touch ~/myFile

• 13. Copy the file to the directory previously created using the "cp" command, then delete the original file using the "rm" command.

    $ cp ~/myFile ~/myDir/myFile
    $ rm ~/myFile

• 14. Move the remaining copy to the user directory using "mv", move now to the directory you created and bring the file back there again.

    $ mv ~/myDir/myFile ~
    $ cd ~/myDir
    $ mv ../ .

• 15. Make a copy of your directory and its file, in a new directory, using of "cp" using the appropriate option, what do you notice?

    Running just "cp" will not work for copying directories,
    We need to add "-r" option.
        $ cp -r . ../myDir2

• 16. Again make a copy of the source directory and its contents inside the last directory created.

    $ cp -r . ../myDir2/myDir3

• 17. Create a symbolic link (shortcut) of the file with the longest tree structure to the first directory with the command "ln", then delete everything with a single command without asking for confirmation

    $ cd ; tree

    $ ln -s myDir/myDir2/myDir3/myFile .

    $ rm -r ~/*

• 18. Create a text file containing a few lines without having to use an editor using the command "cat> file" use the Ctrl-C combination to terminate

    $ cat > myFile 

• 19. Display the contents of the file using the "cat" command while numbering the files. lines.

    $ cat -n myFile

• 20. Display myFile page by page by concatenating the empty lines without breaking the lines long using "more"

    $ more -s myFile

• 21. Display your file page by page with a long prompt (display of the percentage of browsed file) by displaying special characters without filling empty lines with ~ using "less"
  • First methode

    $ grep '\S' jj | cat -e | less -M +Gg

• Secound methode

    $ awk NF jj | cat -e | less -M +Gg