Variable
NAME="John"
echo $NAME
echo "$NAME"
echo "${NAME}
Condition
if [[ -z "$string" ]]; then
echo "String is empty"
elif [[ -n "$string" ]]; then
echo "String is not empty"
fi
Chain command
Chain if the first command succeds
apt update -y && apt upgrade -y
Chain if the first command fails
apt update -y || sudo apt update -y
Pipe
ls -l | grep "config"
Disk Space
df -h
Search
find . -name "*.txt"
Output
ls > files.txt