$SYS_NAME=`uname -s`;
if ($SYS_NAME =~ "AIX") {
   $SYS_TYPE=1;
   `/usr/bin/df -k | /usr/bin/sort +6 >$FILE`;
}
# ...

##</code><code>##

my @df_stdout;
if ($^O =~ /aix/i) {
   $SYSTYPE=1;
   @df_stdout = `/usr/bin/df -k | /usr/bin/sort +6`;
   my $rc = $? >> 8;
   $rc == 0 or die "error: df command failed, rc=$rc";
}
# ...
for (@df_stdout) {
   # Put your while loop body here...
}

##</code><code>##

for (@df_stdout) {

##</code><code>##

for my $line (@df_stdout) {