newbit: what this bash script means?

hi,

I want to know what this bash script part means.

if [ ! $FLIST -ef $WDIR/file.list ]; then
cp $FLIST $WDIR/file.list
fi

$FLIST contains file name string list.
$WDIR is a temporary folder name that was creadted from previous
command.
I can't understand what [ ! $FLIST -ef $WDIR/file.list ] condition
means.

Thanks!

.