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copied!<p>I've seen this one - it confused me, too.</p> <p>The terminal is echoing <code>^D</code> and then the <code>0</code> is output from the program, overwriting the caret.</p> <p>You can demonstrate this by changing the print format in your program to <code>"\n%d\n"</code>.</p> <hr> <p>When asked 'Why?', I went exploring. The answer is in the tty settings. For my terminal, the output from <code>stty -a</code> is:</p> <pre><code>speed 9600 baud; 65 rows; 120 columns; lflags: icanon isig iexten echo echoe -echok echoke -echonl echoctl -echoprt -altwerase -noflsh -tostop -flusho pendin -nokerninfo -extproc iflags: -istrip icrnl -inlcr -igncr ixon -ixoff ixany imaxbel iutf8 -ignbrk brkint -inpck -ignpar -parmrk oflags: opost onlcr -oxtabs -onocr -onlret cflags: cread cs8 -parenb -parodd hupcl -clocal -cstopb -crtscts -dsrflow -dtrflow -mdmbuf cchars: discard = ^O; dsusp = ^Y; eof = ^D; eol = <undef>; eol2 = <undef>; erase = ^?; intr = ^C; kill = ^X; lnext = ^V; min = 1; quit = ^\; reprint = ^R; start = ^Q; status = ^T; stop = ^S; susp = ^Z; time = 0; werase = ^W; </code></pre> <p>Notice the <code>echoctl</code> at the end of the second line - it is for 'echo control characters'.</p> <pre><code>$ stty -echoctl $ cat > /dev/null asdsadasd $ stty echoctl $ cat > /dev/null asasada^D $ </code></pre> <p>You can't see it, but for each <code>cat</code> command, I typed a <kbd>Control-D</kbd> at the end of the line of <code>asd</code> characters, and a second one after hitting return. The prompt erased the second echoed <code>^D</code> in the second example.</p> <p>So, if you don't like the control characters being echoed, turn the echoing off:</p> <pre><code>stty -echoctl </code></pre> <p>The shell can also get in the way; I experimented with <kbd>Control-R</kbd> and my shell (<code>bash</code>) decided to go into</p> <pre><code>(reverse-i-search)`': aasadasdadadasdadadadadadsad </code></pre> <p>I'd typed the unoriginal sequence of 'asd' characters and then typed <kbd>Control-R</kbd>, and this is where I ended up in the shell. I interrupted; I'm not sure what a reverse-i-search is, but I suspect it is Emacs-ish; it was not what I expected.</p>

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