You are viewing the version of this documentation from Perl blead. This is the main development branch of Perl. (git commit 976e22d2a34c45ee8065026229683c7d0c841f46)
join EXPR,LIST

Joins the separate strings of LIST into a single string with fields separated by the value of EXPR, and returns that new string. Example:

my $rec = join(':', $login,$passwd,$uid,$gid,$gcos,$home,$shell);

Beware that unlike split, join doesn't take a pattern as its first argument. Compare split.