printing a linux variable with php shell access - php

Question

I'm trying to echo a variable which is defined in Linux (Centos 6.3).
For accessing the server I use phpseclib 2.0.
When accessing using PuTTY (or similar), with vfrepc86 user, i'm getting the following output:
vfrepc86#illin935!:vfrepc86> echo $USER
vfrepc86
vfrepc86#illin935!:vfrepc86> pwd
/vfuser1/vfr/abp/vfrepc86
vfrepc86#illin935!:vfrepc86> echo $WL_HOME
/opt/weblogic1211_new/wlserver_12.1
When I try running the same with PHP (connecting with the same user vfrepc86), using the following code:
<?php
set_include_path(get_include_path() . PATH_SEPARATOR . 'phpseclib');
include('phpseclib/Net/SSH2.php');
$ssh = new Net_SSH2('illin935');
if (!$ssh->login('vfrepc86', '******')) {
exit('Login Failed');
}
echo "---User:---";
echo "<br>";
echo $ssh->exec('echo $USER');
echo "<br><br>";
echo "---Location of run:---";
echo "<br>";
echo $ssh->exec('pwd');
echo "<br><br>";
echo "---Default:---";
echo "<br>";
echo $ssh->exec('echo $WL_HOME'); //my first try, returns nothing
echo "<br><br>";
echo "---Using su:---";
echo "<br>";
echo $ssh->exec('su - vfrepc86 -c \'echo $PATH\''); //tried with su
echo "<br><br>";
echo "---Writing to file:---";
echo "<br>";
echo $ssh->exec('echo $WL_HOME >> temp.txt'); //tried writing to file
?>
I get the following:
---User:---
vfrepc86
---Location of run:---
/vfuser1/vfr/abp/vfrepc86
---Default:---
---Using su:---
standard in must be a tty
---Writing to file:---
You can see I'm not able to get the $WL_HOME. Though the script is running from the same path. As seen above, I've also tried using su but that returns standard in must be a tty. Printing the command to a file doesnt help, as the file gets empty.

Answer 1

NET_SSH2 does not request an interactive shell, so your .profile doesn't get executed. That's why $WM_HOME is not defined.
Instead of phpseclib, use the PECL ssh2 extension, it has a function ssh2_shell that requests an interactive shell.

Answer 2

Two solutions.
Enable a PTY ($ssh->enablePTY()) and then do $ssh->exec('command'). More info: http://phpseclib.sourceforge.net/ssh/pty.html
Use an interactive shell. eg. $ssh->read('[prompt]'); $ssh->write("command\n"); echo $ssh->read('[prompt]');. More info: http://phpseclib.sourceforge.net/ssh/examples.html#interactive