while - perform a set of commands multiple times — fish-shell 4.8.1 documentation

# while - perform a set of commands multiple times

## Synopsis

    while CONDITION; COMMANDS; end

## Description

while repeatedly executes `CONDITION`, and if the exit status is 0, then executes `COMMANDS`.

The exit status of the while loop is the exit status of the last iteration of the `COMMANDS` executed, or 0 if none were executed. (This matches other shells and is POSIX-compatible.)

You can use and or or for complex conditions. Even more complex control can be achieved with `while true` containing a break.

The -h or --help option displays help about using this command.

## Example

    while test -f foo.txt; or test -f bar.txt ; echo file exists; sleep 10; end
    # outputs 'file exists' at 10 second intervals,
    # as long as the file foo.txt or bar.txt exists.