Write a for loop in Bash

Occasionally I need to run the same shell command or set of commands in a loop. The one-liner syntax for doing this in bash or zsh is:

for i in {1..10}; do echo $i; done

Multiple commands can be run:

for i in {1..10}; do echo "$i*2"; echo $((i*2)); echo "----"; done

And a step value can also be given:

for i in {1..10..2}; do echo $i; done