I'm in the Linux system terminal input the following command:
$head/dev/urandom | tr - dc | 0-1 head - 16 c

Repeatedly, the results are as follows:


The problem is:
Performed for the first time, and can't output 16 characters, must perform more than two and can output 16 characters,
Tried many times, it is the case, and the first output the number of characters, are less than 16 characters,

Great god, please help to explain the reason, thank you!!!!!!

CodePudding user response:

You try
Cat/dev/urandom | tr - dc | 0-1 head - 16 c

Feel head/dev/urandom random number 0/1 enough