Linux System Administration for Beginners
Essential Commands
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 pageb
to scroll back one page
Searching inside less
:
- Press
/
- Enter your search term (e.g.,
debug
) - Hit
Enter
- Use
n
for next match andN
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 pageEnter
for the next line
Quit more
:
q
Comparing less vs more
Pager | Use Case | Primary Navigation |
---|---|---|
less | Advanced, searchable viewing | j /k , Space , /search |
more | Simple, sequential paging | Space , Enter |
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
Note
Vim’s modal design separates navigation from text entry. Mastering mode transitions is the first step.
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
- Press
/
- Type your search (e.g.,
is
) - 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
Action | Command | Description |
---|---|---|
Copy line | yy | Yank (copy) the current line |
Cut line | dd | Delete (cut) the current line |
Paste after | p | Put (paste) after the cursor |
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
Warning
Using :q!
will discard all unsaved changes. Be sure you intend to lose your edits before forcing a quit.
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
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