Stick the names you are looking for in an array and splice them out as they are found. When the array is empty, all your jobs are done.

Update: See benizi's post below for an important correction to this untested logic.

my @dirs = qw[  ... ];
my @rFiles = map{ "$_/analysis_completed" } @dirs;

while( @rFiles and sleep 15 ) {
    -e $rFiles[ $_ ] and splice @rFiles, $_ for 0 .. $#rFiles;
}

print "All done";
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