Unquoted heredocs and shell expansion silently corrupted code in two successive commits

A developer discovered that using an unquoted heredoc delimiter in bash caused the shell to process backslashes, silently converting the regex token \w into the literal letter w — producing a valid but broken pattern. The corrupted regex was committed and rewrote dozens of file paths into nonexistent strings across four files. The following day, a similar mistake occurred when backtick-enclosed filenames inside a double-quoted shell string were interpreted as command substitutions, stripping words from a Japanese-language spec document. Both errors exited with code 0, producing no visible runtime errors and bypassing any automated checks. The author's takeaway is that any string containing backslashes or backticks should be written to a file rather than passed inline, and that reviewing the diff before committing would have caught both issues immediately.