Adding DD Unix command in Perl

asha_mail has asked for the wisdom of the Perl Monks concerning the following question:

Example:

$a=`dd if=/dev/$cmd of=/dev/null bs=4096 count=2 > ddlog.txt 2>&1`;
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$cmd is variable used to give user input from drop down box. At run time if i give

$a=`dd if=/dev/ram0 of=/dev/null bs=4096 count=2 > ddlog.txt 2>&1`;
the output is printed on terminal but i want it to display in textbox.
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Re: Adding DD Unix command in Perl by JavaFan (Canon) on Dec 09, 2011 at 10:47 UTC
I'm a bit surprised you are saying the output is printed on the terminal. You're redirecting both STDOUT and STDERR to ddlog.txt. Perphaps your implementation of dd writes to the terminal, but if I execute your command, the output gets written to ddlog.txt.	[reply]
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Re: Adding DD Unix command in Perl by pvaldes (Chaplain) on Dec 09, 2011 at 12:57 UTC
wrong idea, this does nothing usefull `if=/dev/ram0 of=/dev/null` Don't mess with dd unless you know what are you doing, this is a potentially very dangerous command in the wrong hands. You'll need to run your perl script as root in any case, a double bad idea. if you want to overwrite the ram with null values, you need to do THIS instead `if=/dev/null of=/dev/ram0` Don't claim to me if you finish deleting your entire filesystem and personal files with dd by mistake.	[reply] [d/l] [select]
Re^2: Adding DD Unix command in Perl by asha_mail (Novice) on Dec 09, 2011 at 13:09 UTC
How to pass perl variable to unix command?	[reply]
Re^3: Adding DD Unix command in Perl by pvaldes (Chaplain) on Dec 09, 2011 at 15:32 UTC
The question really is... What are you trying to do?	[reply]
Re^3: Adding DD Unix command in Perl by ikegami (Patriarch) on Dec 09, 2011 at 20:03 UTC
Why are you asking how to do something you've already done? You can pass arguments to a unix utility by building a shell command like you already did.	[reply]