Syntax for a single-line while loop in Bash
while true; do foo; sleep 2; doneBy the way, if you type it as a multiline (as you are showing) at the command prompt and then call the history with arrow up, you will get it on a single line, correctly punctuated.
$ while true> do> echo "hello"> sleep 2> donehellohellohello^C$ <arrow up> while true; do echo "hello"; sleep 2; done
It's also possible to use sleep command in while's condition. Making one-liner looking more clean imho.
while sleep 2; do echo thinking; done