Demo Pagers and VI

In this lesson, we’ll cover two essential terminal pagers—less and more—and then explore the Vim (VI Improved) text editor. You’ll learn how to view, search, and navigate text in the shell, as well as basic editing workflows in Vim.

Terminal Pagers

Pagers allow you to open large text files inside your shell session and move around without opening a full editor.

less: Feature-Rich File Viewer

The less pager is highly configurable and supports backward navigation, incremental search, and more.

Open a file:

[aaron@LFCS-CentOS ~]$ less /var/log/dnf.log

Navigation keys:

• Up/Down arrows or j/k
• Space to scroll forward one page
• b to scroll back one page

Searching inside less:

1. Press /
2. Enter your search term (e.g., debug)
3. Hit Enter
4. Use n for next match and N for previous match

By default searches are case-sensitive. To ignore case, launch with -I:

[aaron@LFCS-CentOS ~]$ less -I /var/log/dnf.log

Exit less:

q

more: Simple Pager for Quick Viewing

The more pager is straightforward and ideal for quick lookups.

Open a file:

[aaron@LFCS-CentOS ~]$ more /var/log/dnf.log

Basic navigation:

• Space for the next page
• Enter for the next line

Quit more:

q

Comparing less vs more

Vim (VI Improved) Editor

Vim is a powerful modal editor that’s ubiquitous on Linux systems. Understanding its modes is key to efficient editing.

Launching Vim

Start without a file (you’ll assign a name before saving):

[aaron@LFCS-CentOS ~]$ vim

Or open an existing/new file directly:

[aaron@LFCS-CentOS ~]$ vim testfile

Vim Modes

• Normal (default): Navigate & issue commands
• Insert: Enter text
• Command-line: Save, quit, or run Ex commands

Entering Insert Mode

Press i to insert text. You’ll see -- INSERT -- at the bottom.

Type content:

This is our text for our vim demo.

Press Esc to return to Normal mode.

Searching in Normal Mode

1. Press /
2. Type your search (e.g., is)
3. Hit Enter

For case-insensitive matches, append \c:

/is\c

Jump to a Specific Line

In Normal mode, type : plus the line number:

:3

Yanking, Cutting & Pasting

Saving & Exiting

Switch to Command-line mode by typing : in Normal mode, then use:

• :w — write (save)
• :q — quit
• :wq — write and quit
• :q! — quit without saving

Example Workflow

[aaron@LFCS-CentOS ~]$ vim testfile
# (enter Insert mode, make edits, then Esc)
:wq
[aaron@LFCS-CentOS ~]$ cat testfile
no
yes
no
no
no
no
no
yes
new changes
[aaron@LFCS-CentOS ~]$

Additional Resources

• Vim Documentation
• GNU less Manual
• Linux Command-Line Navigation