NAME
while - perform a command multiple times
Synopsis
while CONDITION; COMMANDS...; end
Description
The while builtin causes fish to continually
execute CONDITION and execute COMMANDS as long as CONDITION
returned with status 0. If CONDITION is false on the first time,
COMMANDS will not be executed at all. Hints: use begin; ...; end
for complex conditions; more complex control can be achieved with
while true containing a break.
Example
while test -f foo.txt; echo file exists; sleep 10;
end
causes fish to print the line 'file exists' at 10 second
intervals as long as the file foo.txt exists.