Re^2: Executing a string as a Perl command

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Re^3: Executing a string as a Perl command by petdance (Parson) on May 11, 2011 at 15:00 UTC
The "slow the code down" is so small as to be non-existent. xoxo, Andy	[reply]
Re^4: Executing a string as a Perl command by ikegami (Patriarch) on May 11, 2011 at 15:57 UTC
I agree. It's a question of readability. It requires extra thought to process the unexpected and useless quotes.	[reply]
Re^4: Executing a string as a Perl command by Jenda (Abbot) on May 11, 2011 at 21:10 UTC
Depends. If the variable contains a short string, then the slow down will be negligible. If it contains a number and the subroutine needs to do some more computations, then you've just forced perl to convert the number to a string and back. If nothing more, it's wasteful. Then there is yet another case. What if the variable contains a huge string? You've just made yet another copy ... Jenda Enoch was right! Enjoy the last years of Rome.	[reply]
Re^5: Executing a string as a Perl command by petdance (Parson) on May 13, 2011 at 22:08 UTC
If it contains a number and the subroutine needs to do some more computations, then you've just forced perl to convert the number to a string and back. Which is still negligible, especially when one is about to spawn another process. xoxo, Andy	[reply]
Re^4: Executing a string as a Perl command by dbs (Sexton) on May 11, 2011 at 18:56 UTC
I thought using eval in that way, on a scalar to execute a command is a NO-NO for security and not best practice! cant you just use the qx or system call?	[reply]
Re^5: Executing a string as a Perl command by ctilmes (Vicar) on May 16, 2011 at 10:56 UTC
I thought using eval in that way, on a scalar to execute a command is a NO-NO for security and not best practice! cant you just use the qx or system call? You must think about where the scalar came from, and how much you trust that source (taint checking can help you keep track of that, but you still have to think about it), but if you do trust it, it is fine. You similarly have to think about it if you interpolate it (uselessly) into a string. Even more so for qx or system.	[reply]