(SOLVED) Is it possible to make more pins high at the same time ?

I am wondering (because I can not find any information on this) if it is possible to make several pins high or low at the same time (in only one instruction) because I would like the arduino to switch between several high power sources at the same time , and so I can not risk to make any false contacts between the sources.
Thanks … for the very quick respons … and the (portmanipulation) solution

Sure - use Direct Port Manipulation.
For example:
PORTB = 0xFF;
PORTB = 0b11111111;
PORTB = 255;

will all make all outputs on PORTB go high.
Use pinMode on all the pins to declare them as outputs in setup.

Thanks , for the very quick respons ... this is exactly what I needed ;-))