System() in php

[Marvin_G]

hello guys, i'm using system() command in php to execute command in terminal through php but it seems like there's a problem occured. Below is the simple code in php

<?php
$command = system('perl -e' print "\xF5\x01\x00\x01\x03\x00\x03\xF5"'>/dev/ttyUSB0 ');
?>

it suppose send command to the serial port and light up my LED but it seems like nothing happened. Please share your idea guys. Thank you.

[Jake Arkinstall]

You're having a quote issue, as you might be able to see above.

Escape the single-quotes which PHP should see as "just another character" instead of "end the string", and you'll be fine (hopefully):

$command = system('perl -e \' print "\xF5\x01\x00\x01\x03\x00\x03\xF5" \' > /dev/ttyUSB0'); 

If that looks messy to you (it does to me), consider the following:

$PerlCommand = <<<CMD
    print "\xF5\x01\x00\x01\x03\x00\x03\xF5";
CMD;
$command = system("perl -e '{$PerlCommand}' > /dev/ttyUSB0"); 

Although I believe you can do the same thing without using perl at all, by simply writing to /dev/ttyUSB0 manually within the terminal, or possibly with PHP if you want to make it even simpler.

[Marvin_G]

You're having a quote issue, as you might be able to see above.

Escape the single-quotes which PHP should see as "just another character" instead of "end the string", and you'll be fine (hopefully):

$command = system('perl -e \' print "\xF5\x01\x00\x01\x03\x00\x03\xF5" \' > /dev/ttyUSB0'); 

If that looks messy to you (it does to me), consider the following:

$PerlCommand = <<<CMD
    print "\xF5\x01\x00\x01\x03\x00\x03\xF5";
CMD;
$command = system("perl -e '{$PerlCommand}' > /dev/ttyUSB0"); 

Although I believe you can do the same thing without using perl at all, by simply writing to /dev/ttyUSB0 manually within the terminal, or possibly with PHP if you want to make it even simpler.

Hello jake,thanks for replying. Actually i did tried to run the command in terminal and it works so i guess the quote is not a big deal.