For a Shift_JIS-to-UTF-8 job on a Mac, choose a text editor that does more than open the file. It should identify the source, make the destination explicit, and expose failure when a character cannot be represented.
This article sets the comparison criteria so that you can decide whether a candidate meets the project's requirements before adopting it. The actual sequence for saving a separate result, reopening it, and comparing the text belongs to STUDIO-531.
The short answer: check four capabilities
For a UTF-8 normalisation job, confirm that the editor can:
- Display the encoding of the opened file
- Handle the encodings you need, including UTF-8, UTF-8 with BOM, and Shift_JIS
- Explicitly switch the encoding used for saving
- Stop and identify the location when a character cannot be represented
The number of supported formats and conversion speed come later. The first requirement is being able to confirm both the source and destination encoding.
Build a comparison table, not a conversion procedure
Fill these four columns for every candidate:
| Criterion | What to confirm | Adoption rule |
|---|---|---|
| Source display | Can the opened file's encoding be checked? | The source is shown rather than guessed |
| Supported formats | Does it handle the encodings required by the hand-off? | Required formats are covered |
| Destination choice | Can the save encoding be selected deliberately? | Source and destination cannot be confused |
| Failure behaviour | Can an unrepresentable character and its location be identified? | The result is not silently treated as complete |
Whether UTF-8 with BOM is needed, and whether line endings must also change, comes from the recipient's specification. Use those requirements to eliminate candidates.
Define rejection rules before choosing
Turn each row in the comparison table into a question that separates adoption from rejection.
- Can the editor display the opened manuscript's encoding instead of leaving it as a guess?
- Can the required UTF-8 and BOM condition be selected as the destination requirement?
- When a character cannot be represented in a chosen destination, can the interruption and location be identified?
- Does the available processing unit fit the project, and can a failed file be identified?
Remove a candidate if it fails any mandatory question. If the official documentation or a controlled sample cannot establish an answer, mark it unverified rather than treating it as satisfied. This section decides which tool qualifies; it does not perform the conversion or prescribe its execution order.
Add book-specific criteria before choosing
If a project has strict requirements for name variants, symbols such as wave dashes, or line endings, add them to the comparison table. A recorded Shift_JIS save returned a full-width tilde for a source wave dash, so symbol-heavy projects should require documentation or a controlled sample test.
When rune Studio is a candidate
rune Studio supports UTF-8, UTF-8 with BOM, Shift_JIS, EUC-JP, ISO-2022-JP, UTF-16LE, and UTF-16BE. In the operation test, separate Shift_JIS and UTF-8 samples were reported as those encodings, so it is a candidate when the current encoding of a long manuscript must be checked.
A reverse-direction test tried to save a UTF-8 manuscript containing 𠮷 as Shift_JIS. No file was written, and the position of the unrepresentable character was reported. This is evidence for the failure-behaviour criterion, not evidence that a Shift_JIS-to-UTF-8 conversion procedure was completed.
The operation record did not verify a folder-wide batch conversion feature. If bulk conversion is mandatory, check that as an additional selection criterion.
Summary
- Choose a Mac UTF-8 text editor by source-encoding display, destination selection, and safe failure behaviour
- Compare supported formats, source display, destination choice, and failure behaviour
- Add project-specific characters, line endings, processing volume, and record requirements to the adoption rules
- Use rune Studio's measured detection and reverse-direction refusal only as evidence for candidate selection
- Leave separate saving, reopening, and text comparison to STUDIO-531
Fill the four-column table for each candidate and remove any tool with a failed or unverified mandatory requirement. Once one tool remains, the separate save, reopen, and text-comparison work moves to STUDIO-531, "Converting to UTF-8: The Three Steps and What to Check at Each One."
See the current product scope on the Rune Studio product page.
