python check if variable is empty

This is very easy to know in python that if any variable is empty or not

try to use :

if not ur_var:
     print "variable is empty 

get attention towards   not   keyword . This does all things .

This is equivalent to empty($ur_var)  in php

not keyword in python also checks for lists (array) , objects , strings , integrers , floats etc ..

example :

a= 0  or a = "" or a ={} or a= []
if not a :
    print "empty"

in all cases it will print empty .

linux set ulimit

for setting ulimit u need to run following command

ulimit -n  10000  for setting limit to 10000

for soft files  
ulimit -Sn  10000

and for hard files
ulimit -Hn 10000


do it individually for all users

and this setting will be vanished after system restart

virtual hosting in nginx

Virtual hosting in nginx is very simple :

see nginx.conf file 

one server block is generally available there .
see


server {
listen 80;
server_name _;

#charset koi8-r;

#access_log logs/host.access.log main;

location / {
   /root //html;
  index index.html index.htm index.php ;
}
}


this is default server setting. that means from all doamains this will work .

for virtual hosting define new server block 
 

:
server {
listen 80;
  server_name yourdomain.com;

#charset koi8-r;

#access_log logs/host.access.log main;

location / {
   /root /new_host;
  index index.html index.htm index.php ;
}
}





now settings have been changed

just restart nginx  and see
if traffic coming from  yourdomain.com  then it will point to /root/ new_host   directory .

else it will go to /root/html  directory and find related contents here.




thats it   . it was very simple



ask me if u want any further help .

php call method froma string with parameters

very simple way to do that 


function abcd($parameter)
{
     return ture ;
}

$meth_str="abcd('ab')";
$res = false;
        $abc = '$res';
        $check = <<<bcd
if($meth_str)
{
        $abc= true;
} else
{
        $abc=false;
}
bcd;

        eval($check.";");    ///   that means $res=true;
     

Hope it helps
if need further help  comment here