Character 13, in ASCII and derived character sets, is Carriage Return (CR). It is a non-printable character that terminals usually interpret as a request to move the cursor to the start of the current line.

It can be represented as \r (at least on Windows and unix systems), \x0D and \015 in Perl string literals to avoid the trouble of actually placing the character in the literal.

Some fun with \r: 

$| = 1;  # Turn off buffering on STDOUT.
print(  "    5"); sleep(1);
print("\r    4"); sleep(1);
print("\r    3"); sleep(1);
print("\r    2"); sleep(1);
print("\r    1"); sleep(1);
print("\r** BOOM **\n");

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In reply to Re: adding non printable characters in perl's print function by ikegami
in thread adding non printable characters in perl's print function by jesuashok

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