#use system command to add user and set passwd
system "useradd -m -p $d1 $d2";
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Please do not do this. Ever.

• useradd requires escalated privileges
• You are not running in taint mode
• You have done no validation on $d1 or $d2
• There is no need for the shell at all here

and that's not even to consider that your choice of variable names ($d1, $d2) means that you have confused them.

Instead: use taint mode and strict, validate your input, give your variables meaningful names and use the exec form of system, eg: system('useradd', @args); If you are writing anything in perl which requires escalated privileges then do please read through all of perlsec first.

Security is always important. If you are giving the user a root shell, it becomes vitally important.