Text Editors - Comprehensive Reference Guide

Overview

Purpose

Text editors are fundamental tools for system administrators. They're used for editing configuration files, scripts, documentation, and source code. Understanding multiple editors ensures you can work in any environment.

The Big Three

vi/vim: Powerful, ubiquitous, modal editor. Available on every Unix/Linux system. nano: Beginner-friendly, non-modal. Good for quick edits. ed: Minimal line editor. Used in scripts and remote sessions.

Modes in vim

Command Mode: Default. Movement and deletion. Insert Mode: Type text. Ex Mode: Execute commands with :. Press Escape to return to Command Mode.

Editor Comparison Chart

Feature	vi/vim	nano	ed
Learning Curve	Steep	Gentle	Steep
Availability	Universal	Common	Universal
Power	Very High	Medium	High
Automation/Scripting	Excellent	Poor	Excellent
Remote Sessions	Good	Good	Best
Resource Usage	Minimal	Minimal	Minimal

vi and vim - The Everywhere Editor

Starting vim

vim filename or vi filename for the original. If file doesn't exist, it's created on save.

COMMAND MODE - Movement and Deletion
`h, j, k, l`	Left, Down, Up, Right (arrow keys also work)
`w, b, e`	Next word, Previous word, End of word
`0, $`	Beginning of line, End of line
`G, gg`	End of file, Beginning of file
`dd, d$, dw`	Delete line, to end of line, word
`yy, y$, yw`	Copy (yank) line, to end, word
`p, P`	Paste after, before cursor
`u, Ctrl-r`	Undo, Redo
`/, ?`	Search forward, backward
`n, N`	Next match, Previous match

COMMAND MODE - Entering Insert Mode
`i, a`	Insert before, after cursor
`I, A`	Insert at beginning, end of line
`o, O`	Open new line below, above
`Esc`	Return to Command Mode (from Insert Mode)

EX MODE - Commands (press : in Command Mode)
`:w`	Write (save) file
`:q`	Quit
`:wq` or `:x`	Save and quit
`:q!`	Quit without saving
`:set nu`	Show line numbers
`:s/old/new/`	Replace on current line
`:%s/old/new/g`	Replace all in file

10 Detailed Examples

Opening and Exiting vim

Command 1: Open a file

vim /etc/hosts

[vim opens showing file contents]
~
~
"/etc/hosts" 3 lines

What This Does:

Opens the /etc/hosts file in vim. The file displays with line numbers (if set). The ~ characters show empty lines beyond the file's end.

To Exit (in Command Mode)

:wq

Saving and Quitting:

:w - Save without exiting
:q - Quit if no changes
:wq - Save and quit
:q! - Quit, discard changes

Inserting Text and Basic Editing

Steps:

1. Press 'i' to enter Insert Mode
2. Type your text
3. Press Esc to return to Command Mode

What This Does:

The most basic editing operation. Insert Mode allows normal text entry. Escape returns you to Command Mode for navigation and deletion.

Insert Mode Variants:

i - Insert before cursor
a - Insert after cursor (append)
I - Insert at line beginning
A - Insert at line end
o - Insert new line below
O - Insert new line above

Finding and Replacing Text

Find and Replace (in Command Mode)

:s/localhost/127.0.0.1/

What This Does:

Replaces the first occurrence of "localhost" with "127.0.0.1" on the current line.

Replace All in File

:%s/localhost/127.0.0.1/g

Breaking It Down:

% - Apply to entire file
s - Substitute command
/old/new/ - Find/replace pattern
g - Global (all occurrences per line)

Advanced Patterns:

:%s/\s\+$/ - Remove trailing whitespace
:%s/^#/ - Remove # from line start
:%s/.*/& &/ - Duplicate each line's content

Deleting Lines and Text

Delete Operations (in Command Mode)

dd - Delete current line
d$ - Delete to end of line
dw - Delete word
5dd - Delete 5 lines
1,5d - Delete lines 1-5 (Ex mode: :1,5d)

What These Do:

All these commands remove text. Deleted text goes to the clipboard and can be pasted with p. These are often combined with counts for efficiency.

Practical Use:

Delete and paste is often faster than manual retyping. For example, dd p moves a line down.

Copying (Yanking) and Pasting

Copy and Paste (in Command Mode)

yy - Copy (yank) current line
y$ - Copy to end of line
5yy - Copy 5 lines
p - Paste after cursor
P - Paste before cursor

What This Does:

Copy text to clipboard without deleting it. Pasting is identical to deleting and pasting—the clipboard is the same buffer.

Use Case Example:

To duplicate a configuration line: position cursor, yy to copy, p to paste below, then edit the duplicate.

Navigating a File Efficiently

Navigation (in Command Mode)

gg - Go to beginning of file
G - Go to end of file
:42 - Go to line 42
/pattern - Search forward for pattern
?pattern - Search backward
n - Next match
N - Previous match

Efficient Navigation:

For large files, use search and line jumping rather than arrow keys. For example, /ERROR finds the first ERROR, then n jumps to the next one.

Production Tip:

Searching with / is much faster than scrolling through thousands of lines. Combine with :set hlsearch to highlight all matches.

Using nano - Beginner-Friendly Editor

Starting nano

nano filename

GNU nano 6.4 filename

[file contents here]

^X Exit ^O Write Out ^R Read File ^Y First Line ^K Cut Text
^C Cursor Pos ^V Next Page ^W Where Is ^U Uncut Text^T To Spell

What This Does:

Nano is much simpler than vim. All commands are shown at the bottom. The ^ means Ctrl key. No modes—just type directly.

Common nano Commands:

Ctrl+X - Exit (prompts to save if changed)
Ctrl+O - Write (save) file
Ctrl+W - Search for text
Ctrl+K - Cut (delete) line
Ctrl+U - Paste
Ctrl+A - Beginning of line
Ctrl+E - End of line

When to Use nano:

Great for quick edits, especially on systems where you haven't configured vim. Less powerful but more intuitive for beginners.

Using ed - Minimal Editor for Scripts

Basic ed Usage

ed myfile.txt

[file size shown]
1
a
[type text]
.
w
q

What This Does:

Ed is a line-oriented editor. Commands are single letters. a appends lines (end with .), w writes, q quits.

Basic ed Commands:

a - Append (add lines)
d - Delete lines
s/old/new/ - Substitute
p - Print lines
w - Write file
q - Quit
. - End of input

Warning:

Ed has minimal feedback and is difficult for interactive use. However, it's scriptable and universal—available on every Unix system.

Editing /etc/hosts with vim

Real-World Example: Add a host entry

vim /etc/hosts
[navigate to end with 'G']
[press 'o' to create new line]
[type: 192.168.1.100 myserver.local myserver]
[press Esc]
:wq

What This Does:

A practical scenario: adding a host entry to /etc/hosts. The key vim operations are demonstrated: navigation (G), inserting (o), and saving (:wq).

Critical Files Often Edited with vim:

/etc/hosts - Host mappings
/etc/hostname - System hostname
/etc/network/interfaces or /etc/netplan/ - Network config
/etc/ssh/sshd_config - SSH configuration
/etc/sudoers (use visudo, not vim directly)

Batch Editing with sed (Non-Interactive)

Command: Edit file without opening editor

sed -i 's/old_value/new_value/g' myfile.txt

What This Does:

Uses sed to replace text without opening an interactive editor. The -i flag modifies the file in-place. Useful in scripts and automation.

Automation Patterns:

sed -i.bak 's/old/new/g' file - Create backup
awk '{print $1}' file > file.tmp && mv file.tmp file - Column extraction
ex -c '%s/^M//' file - Remove Windows line endings

When to Use sed vs vim:

Use sed for automated, repeatable edits in scripts. Use vim for interactive, exploratory editing and complex changes requiring human judgment.

Configuration and Advanced Tips

vim Configuration (.vimrc)

Create ~/.vimrc to configure vim. Common settings: set number (line numbers), set tabstop=4 (tab width), syntax on (syntax highlighting), set hlsearch (highlight search results).

vim Plugins and Extensions

Vim has a huge plugin ecosystem for advanced features. Popular plugin managers: vim-plug, Vundle. For system administration, focus on core vim first.

SSH and Remote Editing

SSH connections to servers use the system's default editor or whatever you specify. Ed is often best for slow/unreliable connections. Set EDITOR=nano or EDITOR=vi as needed.

Emergency Editing

On broken systems, ed might be your only option. Know basic ed commands: 1d (delete line 1), 1a (append after line 1), w (write), q (quit).

Quick Reference - Choosing Your Editor

Situation	Best Choice	Why
System configuration files	vim	Powerful, available everywhere
Quick edit by new admin	nano	Easier to learn quickly
Scripted/batch edits	sed or awk	Non-interactive, automatable
Very slow/unreliable link	ed	Minimal traffic, robust
Complex code editing	vim (with config)	Syntax highlighting, navigation
Emergency single-line fix	ed or sed	Fast, no GUI needed

Troubleshooting Common Issues

Problem: Stuck in vim Insert Mode

Press Esc to return to Command Mode. If Esc isn't responding, try Ctrl+C or Ctrl+[.

Problem: File open but nothing appears

You might be in Command Mode. Try pressing i to enter Insert Mode, or check with typing a command (colon appears at bottom).

Problem: Changes lost

Always save before quitting. In vim, :w saves without quitting. Use :wq or :x to save and quit. Remember to press Esc first if you were in Insert Mode.

Problem: Permission denied when saving

File permissions prevent writing. Use :w !sudo tee % to write with sudo privileges. The % refers to the current filename.