until

Execute consequent-commands as long as test-commands has an exit status which is not zero.

Syntax
      until test-commands; do consequent-commands; done

The return status is the exit status of the last command executed in consequent-commands, or zero if none was executed.

This is a BASH shell builtin, to display your local syntax from the bash prompt type: help until

“The act of bell ringing is symbolic of all proselytizing religions. It implies the pointless interference with the quiet of other people” ~ Ezra Pound

Related macOS commands:

for - Loop command
while - Loop command