Description
string 
escapeshellarg ( string arg )
   escapeshellarg() adds single quotes around a string
   and quotes/escapes any existing single quotes allowing you to pass a
   string directly to a shell function and having it be treated as a single
   safe argument.  This function should be used to escape individual
   arguments to shell functions coming from user input.  The shell functions
   include exec(), system() and the
   backtick operator.