the failure is silent and the variable expansion will be empty, otherwise
the shell will report a bad substitution. This bug can usually be worked
around by omitting the braces: @code{$var}. The bug was fixed in
-@samp{ksh99g} (1998-04-30) but as of 2006 many operating systems were
+@samp{ksh93g} (1998-04-30) but as of 2006 many operating systems were
still shipping older versions with the bug.
Some shells can be extremely inefficient when there are a lot of