Prompt

Learn how to use command line file editors.

Tutorial Video

Walk-Through

Video tutorial: Cyber Skyline NCL Summer Live - Linux Command Line - Sep 14, 2021

This challenge will give you experience running basic Linux commands. To solve these challenges, you will be using a Linux Command Line Interface (aka terminal or shell).

Background:

Editing files in the Command Line Interface (CLI) requires a text-based editor, as graphical tools like Microsoft Word, Textedit, or Notepad aren't available. Common CLI editors include nano, vim, and Emacs. Nano is the simplest, while Vim and Emacs offer more advanced features but come with a steeper learning curve. This guide focuses on nano and Vim.

Guide:

Nano

To open nano, simply type nano into the terminal. File names can also be included as the second argument to the command. For example, nano example.txt will create a file named “example.txt” and will launch the application.

When launched, a list of commands is given at the bottom of the screen. Each command is preceded by a caret character ( ^ ) - this represents the “CTRL” or control key on the keyboard. The caret is used as a shorthand for the CTRL key.

Once in nano, type as you normally would in a graphical text editor. However, the mouse can not be used to change the position of the cursor in the document. Use the arrow keys to move your position within the document. A text cursor will highlight your position in the file.

When you are ready to save and exit, press the CTRL + X characters to trigger the exit process. You will be prompted to save the buffer (buffer is referring to the data) and you can press the “Y” key to save or the “N” key to discard your edits.

Vim

Nano can often be too simple for certain tasks, which may be reason to use Vim. Start Vim by using the vim command and optionally providing a filename: vim example.txt

There are various modes in Vim. The default normal mode in Vim functions as read-only. Press i to enter insert mode (indicated by “INSERT” at the bottom left) where standard typing and deletions are enabled. Press Esc to exit insert mode.

vim in insert mode. Press i to enter insert mode. Press the esc button to escape or change modes.

Visual mode enables copying and pasting. Press v in normal mode to begin selecting text from the cursor. Use arrow keys to expand the selection, then press y to “yank” it. Paste the copied text using the p character key, which will paste the text immediately after your cursor.

vim in visual mode. Press v to enter visual mode. This allows copying and pasting.

To save changes after editing, ensure you're in normal mode, then enter command mode with a colon. If editing is complete, type wq to write and quit, then press Enter. Vim displays a warning when quitting with unsaved changes. To exit without saving, use :q!.

vim in command mode. Press : to enter command mode. A colon appears at the bottom of the window to accept commands. Press enter to execute commands.

Vim Command	Purpose
`:q`	Quit (only if there are no unsaved edits)
`:w`	Save the file
`:wq`	Save the file and quit
`:q!`	Quit without saving

Vim relies on keyboard commands to perform editing tasks due to the lack of on-screen buttons. Only basic features are covered here. Commands like dd , which deletes lines, or shortcuts <SHIFT> + G , which jumps the cursor to the end of a file, become familiar with practice.

Renaming, Copying and Deleting Files

After creating a file with nano or Vim, it can be renamed, copied, or deleted as needed.

Rename a File: mv

Use the mv (move) command to rename a file. Provide the original filename as the first argument and the new name as the second.

For example, mv example.txt newname.txt renames the file in the same directory. Include a different path in the second argument to move the file to another location. Below, the file “example.txt” was renamed to newname.txt, and then was moved to the “/” directory using mv newname.txt /newname.txt.

This screenshot lists the contents of the current directory, which contains the example.txt file. The mv command is used to rename the example.txt file. The current directory listing shows the file has been renamed to newname.txt. Then the mv command is used to show that you can move a file to another directory. newname.txt is shown in another directory.

Copy a File: cp

Use the cp (copy) command to duplicate a file. Specify the original filename first and the name of the copy second. For example, cp example.txt copy.txt creates a duplicate named “copy.txt” in the same directory.

This screenshot lists the contents of the current directory, which contains the example.txt file. The cp command is used to make a copy of the example.txt file. After the command is used, the contents of the directory are listed. The copy.txt file has been been added to the directory.

Remove a File: rm

Use the rm (remove) command to delete a file. Specify the filename as the first argument as follows: rm example.txt. This action is permanent and bypasses recovery options like the Recycle Bin. Restoring deleted files typically requires forensic tools.

This screenshot lists the contents of the current directory, which contains the example.txt file. The rm command is used to remove the example.txt file. The directory is shown with the example.txt file gone.

Tools to learn more about text editors:

File Edit

Prompt

Tutorial Video

Walk-Through

Questions

1. What key should you press in addition to the CTRL key to trigger the combination to exit nano?

2. What vim mode allows you to write new characters in the file?

3. What keyboard combination will save and quit the file with vim?

4. What keyboard combination will delete an entire line in vim?

5. What command would you use to rename a file?