Read/write data from command line using PHP

Question

I have a server (debian lenny), spectral analyzer and I have downloaded collection of source codes from Steve Sharples's site. With these s. coudes I am able to connect to spectral analyzer - type command and get the responce.

For example:

my-atom:~/vxi11# ./vxi11_cmd 135.123.106.59
Input command or query ('q' to exit): *IDN?

and I get: Rohde&Schwarz,FSV-7,102004/007,1.50 SP1

Am I able to connect to this server, write command and read the responce using PHP? I was thinking about sockets, but I am not sure if the best choice.

Any help would be most appreciated.

Thanks, Petr

Answer 1

You can execute external programs using exec, shell_exec, system, or proc_open.

I would recommend proc_open, which allows you to set up pipes for stdin, stdout, and stderr.

Check out the proc_open link.

Answer 2

Also you can do like:

$result = `SOME_COMMAND_HERE`;

Answer 3

You can combine shell_exec with netcat:

<?php
$output = shell_exec('echo "TRAC? TRACE1" | netcat -q 1 135.123.106.59 5025');
echo "<pre>$output</pre>";
?>

Note the -q 1 option, which causes netcat to wait for 1 second for the answer. You don't need this wait time on "set" commands. Also, *IDN? does not need the wait time, but many other query commands do.

Using netcat for this connection is dangerously close to the bare metal. You might want to write a shell-script that catches common errors. You can then call that script with shell_exec instead.

The best way of course would be to take Steve Sharples free library and modify his cmd example to suit your own needs.