my $cmd=sprintf("df -k %s |",$FILESYSTEM)  #note the trailing pipe in the format
open PIPE,$cmd or die "$cmd: $!";
my $junk=<PIPE>; # get rid of the first line.. it's junk.
#
#   Could probably use /[\s]+/ but...
my @df=split(/[\s\n\t]+/,<PIPE>)
close PIPE; # done with this.
my $df=$df[4];  #keep in mind the scalar $df is different than the array @df
chomp $df;      # just for grins
$df =~ s/\%//g; # strip the %
printf "File system %s is %d%% used\n",$FILESYSTEM,$df