Capturing External Program Output

[Anon]

• I posted a similar message last night, but it might have mislead some people since it mentioned Windows specifically, so I am posting this as a new topic rather than as a follow-up to my previous post. *

I have been trying to figure out how to capture output from an external program, but I have not been able to get it to work under either Windows 2000 or Linux. Whether I use PassThru(), System(), or backticks, my variables simply do not seem to be receiving the external program output. Does anyone know what I am doing wrong?

I am just using "echo Hello!" here since it does the same thing under both Windows and Linux, but I have also tried "dir" and "ls" on Windows and Linux respectively and received the same results.

<?php

// echo Hello! does the same thing under Windows and Unix.

$Command = "echo Hello!";

echo "<P>\$Command: $Command</P>\n";

// None of these seem to do what I wanted:

$PassThru_Result = passthru($Command) or $PassThru_Result = "&quot;\$PassThru_Result = passthru(\$Command)&quot; did not work!";

echo "<P>\$PassThru_Result: $PassThru_Result</P>\n";

$System_Result = system($Command) or $System_Result = "&quot;\$System_Result = system(\$Command)&quot; did not work!";

echo "<P>\$System_Result: $System_Result</P>\n";

$Backticks_Result = `$Command` or $Backticks_Result = "&quot;\$Backticks_Result = `\$Command`&quot; did not work!";

echo "<P><SPAN CLASS=\"Bold\">\$Backticks_Result:</SPAN> $Backticks_Result</P>\n";

?>

Any help would be much-appreciated! Thanks in advance! 🙂

[Anon]

well, for one the Command is not being passed to an actual program! don't know if that's just an example.

And two just curious what program are you attempting to read output from. That might help as well.

COPE

[Anon]

So none of these...

$PassThru_Result = passthru($Command);

$System_Result = system($Command);

$Backticks_Result = `$Command`;

... will execute a command then? If not, how is that done?

For one thing, I would like to be able to read ls (UNIX) and dir (Windows) results without using specialized functions. I would also like to be able to execute other things eventually, but I don't have a specific program I need to execute just yet. I just want to be able to do it. 🙂

[Anon]

Hi,

Directories?! That's it?! Ok. But you MUST write your own function any other way would be slow , difficult, a security hazard. Please read the file section from php.net dictionary.

Last but not least you are ussing passthru incorrectly. The correct form is as follows:

Passthru
(command [,<i>return_var</i>])

returns:
nothing

function:
executes specific command and displays RAW OUTPUT

---

system does similar. except it displays ANY output. and returns a string.

system( command [,<i>return_var</i>])

Hope that helps. Though you really need to write your own function. It's not as hard as it may seem!

Peace
COPE

[Anon]

Thanks you! I had the syntax wrong. I did read the manual pages, but I didn't realize that I had to include the return variable that way; code snippets other people had posted included it as an assignee with a standard-looking variable assignment statement.

No, it is not just for directories; that is just for starters. I need to be able to capture some external program output for a project at work, but I haven't been provided with all of the details just yet, so I was just using directory listings and echo statements to figure out how to get it to work so I will be ready when I have to actually use it.

I must write my own function to retrieve directory contents and such or to capture external program output? I can see how it might be faster to simply read all of the directory contents via a PHP statement then go straight to output formatting and skip the step of parsing, which would be necessary otherwise.

What is the security issue? I come from a Perl background, so I already know better than to pass any user input to the command line and I know that letting just anyone see complete directory listings could pose a security problem. Is there something else I should be aware of?

Thanks again! 🙂

[Anon]

Glad I could help

Well firslt the security issue arises from the black box syndrome. You are out sourcing data in to the black box (external program) and expect a result which is then parsed.

The problem lies in the fact that it may be fine for now. But what happens when you need to upgrade soulution change hardware ect. ,. What happens when you need to refine your solution to be more user friendly or more functional? You have to lean on that crutch (black box) in order to provide a certain level of functionality.

Last but not least you mostly likely are not privy to the code that program contains! what if there is come bug hidden away in it's code that is just itching to so itself?! If that app becomes miossion critical it will destroy whatever foundation is set around it. And could cost you down-time rushing to fix the little wheel solution.

So for those reasons I strongly suggest writting your own code. Plus it's just as fast as a c command might be. and if you REALLY need the direct writes to the drive, the code IS open source. and the it can be ammended to fit your needs from the root.

Well, keep working sounds good . That's great you are plaing ahead, kudos. lol

Well, Good luck. And let me know how it turns out,

COPE