PHP never testing true for file_exists while evaluating array value

Question

My problem is I set an array value to the name of a server as follow:

$appserver[$i]=`grep $ip[2] /etc/hosts |awk '{print $2}'`;

Later I do a test to see if the server is up or not (using a wget). If the test fails I keep track of that server being down by creating a file with that name using touch:

$touch=`touch /home/steve/data/$appserver[$i];

The file gets created successfully. Later when I go to test whether or not the file exists it never evaluates to true.

if(file_exists('/home/steve/data/$appserver[$i])) {

I have tried several different things including creating a new variable for $appserver[$i] and testing against it, which also does not work:

I am running php 5.1.6 on RHEL 5.

Here is the full code:

  $appserver[$i]=`grep $ip[2] /etc/hosts |awk '{print $2}'`;
  echo "appserver[i] = $appserver[$i]\n";
   $get=`wget $key->url 2> /dev/null`;
   if(file_exists('/home/user/Start')) {
            $color[$i]="green";
            $rm=`rm -rf /home/user/Start`;
    }
    else {
            $color[$i]="red";
            if($hostname=="xxxxx" ) {
                    **if(file_exists('/home/user/data/$appserver[$i]))**  {**
                        echo "do nothing appserver file exists\n";
                        $touch=`touch /home/steve/data/notmailed`;
                        }
                    else {
                    echo "No app file mailed alert\n";
                    $touch=`touch /home/user/data/$appserver[$i]`;
                    }
            }
    }

Thank you.

Answer 1

It should be:

if(file_exists("/home/steve/data/$appserver[$i]")) {

Answer 2

if(file_exists('/home/steve/data/$appserver[$i]')) {

' quoted strings do not interpolate variable values, so you're looking for a file whose literal name is $appserver[$i]. Use " quotes instead:

if(file_exists("/home/steve/data/$appserver[$i]")) {

Answer 3

Try this:

$appserver[$i] = "grep $ip[2] /etc/hosts |awk '{print $2}'";

//...

if(file_exists("/home/steve/data/$appserver[$i]"))
{
    //...
}

Ensure that you use double-qoutes (") whereever you want the content of variables parsed into the declared string!