executes the specified command and returns a $handle.$ exec(@command, [%env], ["directory"])
executes the first element of the command array and returns a $handle. this form of exec is useful for passing arguments that have whitespace in them.
"command" - the comamnd to execute. this string is split apart by whitespace. the first token represents the command. the rest of the string is split by whitespace and passed as arguments.
@command - an array containing the command to execute as element 0. The rest of the array is passed as the argument array for the command.
%env - a scalar hash specifying the environment for the executed command. (default is $null which uses the default environment).
"directory" - the directory to execute the command from. default is the current working directory.
A $handle to stdin/stdout for the executed process. This handle can be read from and written to using Sleep's IO functions.
$process = exec("ls -al"); @data = readAll($process); closef($process);