STDERR and exits with
the current value of $! (errno).  If $! is 0, exits with the value of
($? >> 8) (backtick `command` status).  If ($? >> 8) is 0,
exits with 255.  Inside an 
eval()
, the error message is stuffed into 
$@
,
and the 
eval()
 is terminated with the undefined value; this makes 
die()
the way to raise an exception.
Equivalent examples:
If the value of EXPR does not end in a newline, the current script line number and input line number (if any) are also printed, and a newline is supplied. Hint: sometimes appending ``, stopped'' to your message will cause it to make better sense when the string ``at foo line 123'' is appended. Suppose you are running script ``canasta''.
produce, respectively