3.2.78 join

join 

EXPR

, 

LIST

This function joins the separate strings of LIST into a single string with fields separated by the value of EXPR , and returns the string. For example:

$_ = join ':', $login,$passwd,$uid,$gid,$gcos,$home,$shell;

To do the opposite, see split . To join things together into fixed-position fields, see pack .

The most efficient way to concatenate many strings together is to join them with a null string.