\section while while - perform a command multiple times \subsection while-synopsis Synopsis <tt>while CONDITION; COMMANDS...; end</tt> \subsection while-description Description <tt>while</tt> repeatedly executes <tt>CONDITION</tt>, and if the exit status is 0, then executes <tt>COMMANDS</tt>. If the exit status of \c CONDITION is non-zero on the first iteration, \c COMMANDS will not be executed at all. Use <a href="#begin"><tt>begin; ...; end</tt></a> for complex conditions; more complex control can be achieved with <tt>while true</tt> containing a <a href="#break">break</a>. \subsection while-example Example <tt>while test -f foo.txt; echo file exists; sleep 10; end</tt> outputs 'file exists' at 10 second intervals as long as the file foo.txt exists.