Creating and Editing Text Files with Vim

Hello again. In the previous lesson, you learned to inspect files safely with tools such as less, head, and tail. Inspection comes first; editing comes only after you have confirmed the correct file and understood its current contents.

This final lesson in the command-line foundations module introduces Vim, the terminal editor found on virtually every enterprise Linux system in some form. By the end, you will be able to create a text file, make controlled changes, search within it, recover from basic mistakes, and save or discard your work deliberately.

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Vim’s central idea: modes

Most graphical editors let you type as soon as they open. Vim behaves differently: it is a modal editor. A key’s meaning depends on the current mode.

Vim starts in normal mode. In normal mode, keys are editing instructions rather than text. For example, j moves down a line, x deletes a character, and dd deletes a line. To type ordinary text, you first enter insert mode. To save, quit, or issue an editor command, you use Vim’s command-line mode, entered with : from normal mode.

The practical cycle is:

1. Open a file; Vim begins in normal mode.
2. Enter insert mode when you need to type.
3. Press Esc to return to normal mode.
4. Use a colon command to save, quit, or perform another editor action.

When uncertain about your current state, press Esc once or twice. It does not discard your work; it simply returns you to normal mode.

A vocabulary note: some guides call Vim’s default state command mode, while others call it normal mode. In this lesson, normal mode means the default state for navigation and editing keystrokes. The state reached by pressing : will be called command-line mode.

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Open a safe practice file

For now, work only in a directory under your home directory. Do not practice on files in /etc, service files, or other system configuration. A single unwanted save to a system file can change system behavior.

First create a dedicated workspace at the shell prompt:

mkdir -p ~/vim-lab
cd ~/vim-lab
pwd

The final command should show a path ending in vim-lab. Check whether the full vim command is available:

command -v vim

If it prints a path such as /usr/bin/vim, use vim throughout this lesson. If it produces no output but the following command prints a path, you can use vi instead:

command -v vi

On RHEL-compatible systems, vi may be a minimal Vim-compatible editor. The commands practiced here remain applicable.

Open a file that does not yet exist:

vim notes.txt

At this moment, Vim has opened an empty buffer associated with the name notes.txt. The actual file is created only when you successfully write it to disk.

A useful distinction will prevent many beginner errors:

What you enter	Where you enter it	Meaning
vim notes.txt	Shell prompt	Start Vim and open or create a file
i, o, dd, u	Vim normal mode	Single-key or short editing commands
:w, :q, :wq	Vim command-line mode	Commands that start with : and finish with Enter
Ordinary text	Vim insert mode	Content that becomes part of the file

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Create the file: insert, escape, write

With the empty file open, press lowercase i. The lower part of the Vim screen should show -- INSERT -- or an equivalent insert-mode indicator.

Type the following three lines exactly:

# Basic Vim lab
host=lab01
environment=training

Press Enter after the first and second lines. When done, press Esc. The insert indicator disappears: you are back in normal mode.

Now save the file:

1. Press :.
2. Type w, so the bottom line reads :w.
3. Press Enter.

The w means write. Vim should report that notes.txt was written. You remain inside the editor, which is useful when you want to save progress without stopping work.

Quit only after the write completes:

1. Press :.
2. Type q.
3. Press Enter.

Back at the shell, verify that the file exists and contains what you intended:

cat ~/vim-lab/notes.txt

This is the inspect-then-edit discipline from the previous lesson in reverse: after editing, inspect the resulting file to confirm the saved content.

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Put text in the right place

Reopen your lab file:

vim ~/vim-lab/notes.txt

Vim opens in normal mode. Arrow keys generally work, but learn a few normal-mode navigation keys as well. They work reliably over an SSH connection and avoid moving your hands away from the typing position.

Normal-mode key	Result
h, j, k, l	Move left, down, up, and right
0	Move to the first character of the current line
$	Move to the end of the current line
w	Move forward by a word
b	Move backward by a word
gg	Go to the start of the file
G	Go to the end of the file

The essential insertion commands choose where typing begins:

Key in normal mode	Result
i	Insert before the cursor
a	Append after the cursor
I	Insert at the start of the current line
A	Append at the end of the current line
o	Open a new line below and enter insert mode
O	Open a new line above and enter insert mode

For an administrator editing a configuration file, A and o are particularly convenient. A adds a value to an existing line; o creates a separate directive immediately below the current line.

Try this controlled modification:

1. Use G to move to the final line.

2. Press A.

3. Add this text at the end of the existing line:

   -updated
   

   The complete line becomes environment=training-updated.

4. Press Esc.

5. Press o to create a new line below it.

6. Type:

   owner=student
   

7. Press Esc.

8. Save with :w.

At this point, your file has four lines. Press :q to leave it, then inspect it with:

cat ~/vim-lab/notes.txt

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Correct mistakes without panic

Vim is safest when you treat normal mode as the place for precise operations rather than holding Backspace until the text looks right. Start with these commands:

Normal-mode command	Result
x	Delete the character under the cursor
dw	Delete from the cursor through the rest of a word
dd	Delete the current line
u	Undo the most recent change
Ctrl+r	Redo a change that was undone
yy	Copy, or “yank,” the current line
p	Paste copied or deleted text below the current line

To see why undo matters, position the cursor on the owner=student line and press dd. The line disappears. Press u immediately and it returns.

Deleting a line also stores it in Vim’s temporary register, so p can paste it below the current line. That makes dd followed by p a quick way to move a line downward one position. For your first few sessions, use u freely. It is usually better to undo promptly than to make several compensating edits that are difficult to review.

A small but important point: commands such as dd and dw work only in normal mode. If you accidentally type dd while -- INSERT -- is visible, Vim will insert the letters dd into the file. Press Esc, use u if necessary, and continue.

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Find a setting before changing it

Configuration files often contain comments, repeated options, and settings far from the current cursor position. Searching is more reliable than scrolling.

From normal mode:

1. Type /environment.
2. Press Enter.

Vim searches forward for environment and places the cursor on a match. Press n to visit the next match, or N to go to the previous match.

For example, edit notes.txt again and search for host:

vim ~/vim-lab/notes.txt

Use /host, press Enter, then press A to move directly to the line’s end and enter insert mode. Add a descriptive comment:

 # training system

The full line becomes:

host=lab01 # training system

Press Esc and use :w to save. Search first, then make the local change. This pattern will transfer directly to larger configuration files later in the course.

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Save, quit, and discard with intent

The commands below are all entered from normal mode. Press Esc first if needed, then type the colon command and press Enter.

Command	Meaning	Appropriate use
:w	Write the current file and continue editing	Save progress and keep working
:q	Quit	Leave after saving, or when no changes were made
:wq	Write, then quit	Save the completed edit and return to the shell
:q!	Quit and discard unsaved changes	Abandon an incorrect experiment deliberately

The exclamation mark in :q! means “force.” It is valuable when you realize an edit is wrong, but it removes all unsaved changes in the current file. Do not use it as a response to every Vim message. First read the message: a failure to write might mean that you opened the wrong path, the directory does not exist, or you lack permission.

For system configuration later in the course, a failed save is a signal to stop and verify the file, ownership, permissions, and approved privilege method. Do not turn a practice habit into a risky one by casually forcing writes or editing protected files as root.

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A short independent Vim routine

Use this sequence once without looking back at the command tables:

1. At the shell, open a new file:

   vim ~/vim-lab/service-notes.txt
   

2. Enter insert mode and create these lines:

   service=httpd
   state=enabled
   port=80
   

3. Escape to normal mode and write the file with :w.

4. Search for state with /state.

5. Use A to append # desired at boot to that line.

6. Press Esc, save and quit with :wq.

7. Confirm the final result without opening Vim:

   cat ~/vim-lab/service-notes.txt
   

This workflow is intentionally small, but it contains the core of routine configuration editing: open a known file, find the target setting, make one local change, save, and verify the resulting text.

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Key takeaways

Vim becomes manageable once you keep its modes distinct:

• Vim starts in normal mode, where keys perform actions rather than insert text.
• Use i, a, A, o, and O to enter insert mode at the right location.
• Press Esc to return to normal mode before navigating, deleting, searching, saving, or quitting.
• Use u to undo, Ctrl+r to redo, and /text followed by n or N to search.
• Use :w to save, :q to quit, :wq to save and quit, and :q! only when you intentionally want to discard unsaved changes.
• Practice in your home directory, verify saved files with read-only commands, and avoid experimenting on live system configuration.

Next, the course moves into filesystem operations: creating, copying, moving, renaming, and removing files and directories safely. Vim will remain useful whenever those operations require you to create a note, modify a configuration file, or document an administration decision.