Desed is a command line tool with beautiful TUI that provides users with
a comfortable interface and practical debugger, used to step through complex
sed scripts.

Some of the notable features include:
* Preview variable values, both of them
* See how will a substitute command affect pattern space before it runs
* Step through sed script, both forward and backwards
* Place breakpoints and examine program state
* Hot reload and see what changes as you edit source code
* Its name is a palindrome

desed currently only supports GNU sed (gsed) because BSD sed doesn't support
the execution annotation feature (the --debug argument of gsed) that desed
depends on.

WWW: https://github.com/SoptikHa2/desed