Linux for Beginners: Disks, File Systems, and APT Packages | Lesson 4
▶ Linux for Beginners Playlist:
• Linux. Begginer course.
In this lesson, you will learn how disks, partitions, and file systems work in Ubuntu in a simple and practical way. We will also cover how to check what is taking disk space, why df and du can show different results, and how to install, update, and remove programs with APT. If you want to feel more confident using Linux in real tasks, this lesson is a great next step.
00:00 Intro
00:30 Disk, Partition, and File System
01:24 EXT4 and XFS
03:15 lsblk Explained
03:59 df -h Explained
04:55 du -sh and Folder Sizes
06:07 Why df and du Show Different Numbers
07:27 Deleted File but Space Was Not Freed
10:32 mount and umount
13:10 /etc/fstab Explained
13:06 Inodes and df -i
14:27 Swap Explained
15:21 APT Basics
16:50 apt update
21:16 Snap, Flatpak, and PPA
23:00 Package Managers in Other Distros
23:42 dpkg -L Explained
24:13 Summary
Commands used in this lesson
Viewing disks, partitions, and mounts
lsblk — show disks, partitions, and mount points
findmnt — show mounted file systems in a tree view
mount | head — show the first lines of currently mounted file systems
cat /etc/fstab — show the file system mount configuration used at boot
Checking disk space and inode usage
df -h — show file system size, used space, free space, and mount points in human-readable format
df -h /tmp — show disk usage for the file system that contains /tmp
df -i — show inode usage for file systems
du -sh ~ — show the total size of the home directory
du -h --max-depth=1 ~ — show the size of first-level folders inside the home directory
du -h --max-depth=1 ~/.cache — show the size of first-level folders inside the .cache directory
Working with large files and open deleted files
fallocate -l 200M /tmp/bigfile.log — create a 200 MB file quickly
tail -f /tmp/bigfile.log — keep the file open and watch it in real time
rm /tmp/bigfile.log — delete the file
lsof +L1 — show open files that have fewer than one hard link, often deleted but still open
lsof | grep deleted — find open files that were deleted
Memory and swap
swapon --show — show active swap areas
free -h — show RAM and swap usage in human-readable format
APT package management
sudo apt update — refresh the package list from repositories
sudo apt upgrade — install available package updates
sudo apt install htop — install the htop package
sudo apt remove htop — remove the package but keep some config files
sudo apt purge htop — remove the package and its related config files
apt search htop — search for a package
apt show htop — show detailed information about a package
Running an installed program
htop — start the htop system monitor
Other package systems
snap list — show installed Snap packages
flatpak list — show installed Flatpak packages
Inspecting package contents
dpkg -L htop — show which files were installed by the package
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