iam new in programming and using linux.

My Question is, is it possible to add Netem Filter Rules later ? I want to create an PHP-Interface for Netem and I don't know how much filters were required. This should be some kind of dynamically.

In Example : A user with a static IP starts an Netem Command (Latency) with PHP Interface

this means these five command werde executed by php

in the first step

$classid = 11; $handle = 10;

"sudo tc qdisc add dev eth0 handle 1: root htb";
"sudo tc class add dev eth0 parent 1: classid 1:1 htb rate 100Mbps";
"sudo tc class add dev eth0 parent 1:1 classid 1:$classid htb rate 100Mbps";
"sudo tc qdisc add dev eth0 parent 1:$classid handle $handle: netem delay 100ms";
"sudo tc filter add dev eth0 protocol ip parent 1:0 prio 3 u32 match ip dst $dest flowid 1:$classid";

Now, if there would be a second user who wants to use Netem independent of the first user, i only want to execute the last 3 commands, like

"sudo tc class add dev eth0 parent 1:1 classid 1:$classid htb rate 100Mbps";
"sudo tc qdisc add dev eth0 parent 1:$classid handle $handle: netem delay 100ms";
"sudo tc filter add dev eth0 protocol ip parent 1:0 prio 3 u32 match ip dst $dest flowid 1:$classid";

There is an Algorithmus for increasing variables $classid and $handle. This should work.

Now my Question: Is it possible only to add these 3 commands to add a new class with new qdisc and a new filter rule ? Or how can i realize it ?

The Apache Error_log tells me "sh: line 1: flowid: command not found" but i can't find any mistake.

I hope you could help

Best regards fontsix