\section while while - perform a command multiple times

\subsection while-synopsis Synopsis
<tt>while CONDITION; COMMANDS; end</tt>

\subsection while-synopsis Synopsis
The <tt>while</tt> builtin causes fish to continually execute the command COMMANDS while the command CONDITION returns with status 0.

\subsection while-example Example

<tt>while test -f foo.txt; echo file exists; sleep 10; end</tt>

causes fish to print the line 'file exists' at 10 second intervals as long as the file foo.txt exists.