Bash to php regexp

Question

I have a bash script that tails a file for a string that contains either "CONNECT" or "DISCONNECT". Once such a string is found that string is then piped to a php sript.

Here is the bash script:

tail -f -n 1 /var/log/connections | grep -P -0 --line-buffered "\bCONNECTED\b|\bDISCONNECTED\b" | php -f $SCRIPT_DIR/connections.php

And here is the php script:

#!/usr/bin/php
<?php

while ( false !== ( $connection_status = fgets ( STDIN ) ) )
{
    $get_status = preg_match ( "/\bCONNECTED\b|\bDISCONNECTED\b/", @$connection_status, $status_match ) ;

    foreach ( $status_match as $status )
    {
        switch ( $status )
        {
            case "CONNECTED": //If the string that got passed to this script (from the BASH script) contains CONNECTED
            {
                print ( "we are connected\r\n" ) ;
            }
            case "DISCONNECTED": //If the string that got passed to this script (from the BASH script) contains DISCONNECTED
            {
                print ( "we are disconnected\r\n" ) ;
            }
        }
    }
}
?>

DISCONNECT works as expected but with CONNECT it returns both "we are connected" and "we are disconnected"

user3783243 · Accepted Answer · 2019-06-19 15:28:06Z

2

Every case requires a break to stop it from running, not {}.

case "CONNECTED": //If the string that got passed to this script (from the BASH script) contains CONNECTED
     print ( "we are connected\r\n" ) ;
break;
case "DISCONNECTED": //If the string that got passed to this script (from the BASH script) contains DISCONNECTED
     print ( "we are disconnected\r\n" ) ;
break;

It is important to understand how the switch statement is executed in order to avoid mistakes. The switch statement executes line by line (actually, statement by statement). In the beginning, no code is executed. Only when a case statement is found whose expression evaluates to a value that matches the value of the switch expression does PHP begin to execute the statements. PHP continues to execute the statements until the end of the switch block, or the first time it sees a break statement. If you don't write a break statement at the end of a case's statement list, PHP will go on executing the statements of the following case.

https://www.php.net/manual/en/control-structures.switch.php

answered Jun 19, 2019 at 15:28

user3783243

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2 Comments

Danny Over a year ago

How foolish of me to have missed that. Thank you

user3783243 Over a year ago

Your foreach also could be removed and you could just use two ifs.

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