The course, at a glance.

pwd

Where am I? · safe · Full example

uname -srmo

Identify your Linux environment · read-only · Full example

ls

List files · safe · Full example

touch file1.txt file2.txt file3.txt

Create first practice items · safe · Full example

cd ~

Move to home and back · safe · Full example

cd ~/linux-practice

Practice parent folders · safe · Full example

cd ~/linux-practice

Return to previous directory · read-only · Full example

cd /etc

Read-only visit to /etc · read-only · Full example

cd ~/linux-practice

Create files · safe · Full example

cd ~/linux-practice

Create and remove empty directories safely · safe · Full example

stat myfile.txt

Inspect file metadata · safe · Full example

echo 'Hello Ubuntu' > myfile.txt

Identify file type · read-only · Full example

cd ~/linux-practice

Write and append · safe · Full example

cat -n journal.txt

Number and reverse lines · safe · Full example

ls -la | tee listing.txt

Save output with tee · safe · Full example

cd ~/linux-practice

Create a large file · safe · Full example

head -n 5 large.txt

Preview file parts · safe · Full example

less -N large.txt

Open with less · safe · Full example

cd ~/linux-practice

Overwrite and append · safe · Full example

ls missing-file 2> error.log

Capture errors · safe · Full example

cat << 'EOF' > document.txt

Use a heredoc · safe · Full example

cd ~/linux-practice

Sort and count · safe · Full example

echo 'Hello World' | tr 'a-z' 'A-Z'

Translate characters · safe · Full example

echo 'Name:Age:City' > people.txt

Cut and align fields · safe · Full example

cd ~/linux-practice

Basic grep · safe · Full example

grep '^A' fruits.txt

Regex anchors · safe · Full example

mkdir -p projects/search-demo

Recursive search · safe · Full example

cd ~/linux-practice

Substitute safely · safe · Full example

sed -n '2p' text.txt

Print selected lines · safe · Full example

sed -i.bak 's/Hello/Hi/g' text.txt

In-place with backup · caution · Full example

cd ~/linux-practice

Print fields · safe · Full example

echo -e 'Product,Price,Quantity\nApple,1.50,100\nBanana,0.75,200' > inventory.csv

CSV separator · safe · Full example

awk -F, 'NR>1 {total += $2 * $3} END {print total}' inventory.csv

Total calculation · safe · Full example

cd ~/linux-practice

Create search lab · safe · Full example

find find-lab -name '*.txt'

Find files · safe · Full example

find find-lab -name '*.txt' -exec ls -lh {} \;

Act on results · safe · Full example

find find-lab -name '*.log' -delete

Delete only after printing · caution · Full example

cd ~/linux-practice

Practice chmod · safe · Full example

echo 'echo Hello' > scripts/hello.sh

Make a script executable · safe · Full example

chmod u+s /usr/bin/passwd

System special bits example · explanation-only · Full example

cd ~/linux-practice

Who am I? · read-only · Full example

touch owned-by-me.txt

Inspect ownership · read-only · Full example

sudo chown username:groupname file.txt

Optional admin ownership examples · optional-admin · Full example

ps

View processes · read-only · Full example

cd ~/linux-practice

Create and stop a practice job · caution · Full example

killall sleep

Broad process killing examples · caution · Full example

printenv | head -20

Inspect variables · read-only · Full example

export MY_NAME='Linux Learner'

Export a temporary variable · safe · Full example

mkdir -p ~/linux-practice/bin

Practice PATH safely · safe · Full example

command -v ls

Find the command your shell will run · read-only · Full example

alias ll='ls -la'

Create and inspect aliases · safe · Full example

unalias ll

Remove aliases · safe · Full example

alias ls='ls --color=auto'

Bypass an alias · safe · Full example

history 10

View history · read-only · Full example

echo 'safe repeat demo'

Repeat simple commands · caution · Full example

history -c

History clearing example · caution · Full example

echo file_{1..5}.txt

Brace expansion · safe · Full example

mkdir -p glob-lab

Globbing lab · safe · Full example

rm -rf glob-lab

Safe cleanup · caution · Full example

cd ~/linux-practice

Hard link demo · safe · Full example

echo 'Target content' > target.txt

Symlink demo · safe · Full example

rm target.txt

Broken symlink · caution · Full example

cd ~/linux-practice

Create archive lab · safe · Full example

mkdir -p backups

Tar and inspect · safe · Full example

mkdir -p restored

Extract safely · safe · Full example

cat ~/.bashrc | head -30

Inspect, do not edit · read-only · Full example

OLD_PS1=$PS1

Temporary prompt · safe · Full example

echo "alias showdate='date +%Y-%m-%d'" >> ~/linux-practice/my_aliases

Practice alias file · safe · Full example

echo "alias la='ls -A'" >> ~/.bashrc

Real .bashrc edit example · explanation-only · Full example

cd ~/linux-practice

Create final project · safe · Full example

cd ~/linux-practice/final_project

Review skills · safe · Full example

cd ~/linux-practice

Remove final project only · caution · Full example

cd ~/linux-practice

Measure sandbox · safe · Full example

df -h /

Filesystem free space · read-only · Full example

lsblk

Observe block devices · read-only · Full example

apt search 'text editor' | head -20

Read-only package search · read-only · Full example

command -v apt || true

Detect your package manager · read-only · Full example

dpkg -l | head -20

Inspect installed files · read-only · Full example

sudo apt update

Optional install/remove pattern · optional-admin · Full example

ping -c 2 8.8.8.8

Connectivity checks · read-only · Full example

getent hosts example.com

Check DNS separately from connectivity · read-only · Full example

mkdir -p ~/linux-practice/downloads

Fetch a web page · safe · Full example

ip addr show | head -30

Inspect network info · read-only · Full example

free -h

Memory and uptime · read-only · Full example

top -b -n 1 | head -20

Process snapshots · read-only · Full example

if command -v journalctl >/dev/null && [ "$(ps -p 1 -o comm=)" = systemd ]; then

Logs and watch · read-only · Full example

cd ~/linux-practice/scripts

Hello script · safe · Full example

cat << 'EOF' > args.sh

Arguments script · safe · Full example

ls /nonexistent

Exit status · read-only · Full example

cd ~/linux-practice/scripts

If/else demo · safe · Full example

cd ~/linux-practice/scripts

For loop · safe · Full example

cd ~/linux-practice/scripts

Case statement · safe · Full example

if ! command -v crontab >/dev/null; then

Read current crontab · read-only · Full example

cd ~/linux-practice

Safe scheduling simulation · safe · Full example

crontab -r

Dangerous cleanup example · explanation-only · Full example

command -v ls

Find command info · read-only · Full example

man ls

Manual pages · read-only · Full example

sudo apt install plocate -y

Optional locate setup · optional-admin · Full example