Lesson 6 - Basic Linux Commands on Ubuntu

In this lesson, we will learn about the basic Linux commands for navigating directories, managing files and directories, as well as viewing and editing files. These commands are essential for effectively operating and managing a Linux system.

1. Navigating Directories

Detailed Examples:

1. List Files and Directories (ls):

   ls
   

   This command lists all files and directories in the current directory.

   Documents  Downloads  Music  Pictures  Videos
   

   To display detailed information including file permissions, owner, size, and modification date:

   ls -l
   

   drwxr-xr-x 2 user user 4096 Apr 10 09:00 Documents
   -rw-r--r-- 1 user user  512 Apr  8 12:30 file1.txt
   

   To display hidden files (those starting with a dot):

   ls -a
   

   .bashrc  .profile  Documents  Downloads
   

2. Change Directory (cd):

   cd /home/user/Documents
   

   This command changes the current working directory to /home/user/Documents.

   cd ..
   

   This command moves up one directory level.

   cd ~
   

   This command changes the directory to the user’s home directory.

3. Print Working Directory (pwd):

   pwd
   

   This command displays the full path of the current directory.

   /home/user/Documents
   

2. Managing Files and Directories

Detailed Examples:

1. Copy Files and Directories (cp):

   cp file1.txt /home/user/backup/
   

   This command copies file1.txt to the /home/user/backup/ directory.

   To copy a directory and its contents:

   cp -r /home/user/Documents /home/user/backup/
   

   This command recursively copies the Documents directory and its contents to the /home/user/backup/ directory.

2. Move or Rename Files and Directories (mv):

   mv file1.txt /home/user/Documents/
   

   This command moves file1.txt to the /home/user/Documents/ directory.

   To rename a file:

   mv oldname.txt newname.txt
   

   This command renames oldname.txt to newname.txt.

   To move and rename a file:

   mv oldname.txt /home/user/Documents/newname.txt
   

   This command moves oldname.txt to /home/user/Documents/ and renames it to newname.txt.

3. Delete Files and Directories (rm):

   rm file1.txt
   

   This command deletes file1.txt.

   To delete a directory and all its contents:

   rm -r /home/user/Documents/
   

   This command deletes the /home/user/Documents/ directory and all files and subdirectories within it.

4. Create a New Directory (mkdir):

   mkdir /home/user/newfolder
   

   This command creates a new directory named newfolder in the /home/user/ directory.

   To create nested directories:

   mkdir -p /home/user/newfolder/subfolder
   

   This command creates newfolder and subfolder inside it if they do not already exist.

3. Viewing and Editing Files

3.1. Vim Editor

Detailed Examples:

1. Open a file in Vim:

   vim file1.txt
   

2. Command mode and insert mode in Vim:

   • Press Esc to enter command mode.
   • Press i to enter insert mode.

3. Save and exit Vim:

   • Type :wq and press Enter to save the file and exit.
   • Type :q! and press Enter to exit without saving.

4. Search and replace text:

   • Type /text and press Enter to search for “text”.
   • To replace text, use the command :%s/oldtext/newtext/g.

5. Delete, copy, and paste lines:

   • Press dd to delete the current line.
   • Press yy to copy the current line.
   • Press p to paste the copied or cut line below the current line.

6. Undo and redo actions:

   • Press u to undo the last action.
   • Press Ctrl + r to redo the undone action.

3.2. Nano Editor

Detailed Examples:

1. Open a file in Nano:

   nano file1.txt
   

2. Save a file in Nano:

   • Press Ctrl + O.
   • Press Enter to confirm saving the file.

3. Exit Nano:

   • Press Ctrl + X.

4. Cut and paste text:

   • To cut, move the cursor to the line to cut and press Ctrl + K.
   • To paste, move the cursor to the position to paste and press Ctrl + U.

5. Search and replace text:

   • Press

   Ctrl + W to search for a term.

   • Press Ctrl + \ to replace a term.

6. Display help:

   • Press Ctrl + G to display the Nano help menu.

Conclusion

In this lesson, you have learned the basic commands to navigate directories, manage files and directories, as well as view and edit files on a Linux system. These commands are essential for effectively operating and managing your system. Practice these commands regularly to become proficient in using them.