3.5. Debugging sed scripts The following two debuggers should
make it easier to understand how sed scripts operate. They can
save hours of grief when trying to determine the problems with a
sed script. (1) sd (sed debugger), by Brian Hiles This debugger
runs under a Unix shell, is powerful, and is easy to use. sd has
conditional breakpoints and spypoints of the pattern space and
hold space, on any scope defined by regex match and/or script
line number. It can be semi-automated, can save diagnostic
reports, and shows potential problems with a sed script before
it tries to execute it. The script is robust and requires the
Unix shell utilities plus the Bourne shell or Korn shell to
execute. (2) sedsed, by Aurelio Jargas This debugger requires
Python to run it, and it uses your own version of sed, whatever
that may be. It displays the current input line, the pattern
space, and the hold space, before and after each sed command is
executed.