I like list expansion:

# Create mutiple directories
mkdir -p {src,data,app/{mobile,web}}

The p switch creates any “missing” parent directories and is idempotent (so if app exists it doesn’t complain and if not creates it).

# Create multiple files
touch file_{1..5}.txt

Heck you can even combine it with tee!

# Create multiple Hello, World! files
echo "Hello, world\!" | tee file_{1..5}.txt