MrkToolsText Editor · macOS
Now that AI does the writing, an editor is a tool for reading and fixing. Logs, CSVs, exports, dumps, diffs. You don’t choose their size or encoding. MrEditor opens them, filters, aligns columns, lets you fix them, and saves without leaving the file half-written.
Free forever · signed and notarized / $19 One-time · up to 2 Macs per license
Files are memory-mapped, and only tens of KB are read before the first line appears. A 1.18 GiB, 5.8-million-line CSV shows its first line in 51 ms; a 10 GB, 86-million-line log opens in about 80 ms. Excel stops at 1,048,576 rows — no rows vanish here.
CSV/TSV align into columns, and one-line JSON is formatted in place. Grep while the columns stay aligned. Formatting is display-only, so saving writes the original back byte for byte. Fixed-width files become columns with the column ruler.
Run jmespath-style expressions with ⌥⌘J to filter and project. Results are never saved, so the file on disk stays untouched.
With tail -f app.log | mreditor, the log opens from the first byte and follows the tail. Type a term while it streams and switch on “matching lines only”: only the matching lines stay, even as the log keeps flowing. Run | mreditor again and the stream joins the open window as a tab. The install command is under Help ▸ Use from Terminal…
sort | uniq -c | sort -rn, on columns or key=value. 3.40 s on a 10 GB, 86-million-line log. Double-click a row and the text narrows to lines with that value.
After filtering to errors, draw the time distribution. Drag a spike and the text becomes that time range, which you can then count by path. 3.18 s on 10 GB and 67 million lines.
One pass over every column: type, blanks, unique count, min/max, sum and mean. 4.78 s on a 1.18 GiB, 30-column file. A map of the CSV before you reach for a spreadsheet.
ssh host:/var/log/app.log (⌃⌘O) opens from the tail. Filtering runs on the remote side and no body bytes are transferred. Authentication is left to /usr/bin/ssh — if the terminal connects, so does this.
Follow mode (⌥⌘F) never reloads; it extends the mmap index by only the new bytes. Follow a multi-GB log that is still being written, and edit it in place.
Atomic save writes to a temporary file and swaps. Bytes you didn’t touch come back as they were. Save as UTF-8 / Shift-JIS / EUC-JP, and pick up outside changes automatically.
Put two files, two open tabs, the clipboard or a URL side by side and see down to the changed character. Press → to move the left side into the right, then save the result under a new name.
Select a stack trace and press ⌥⌘E. The answer streams in as it is written. Anthropic, OpenAI and Gemini use your own API key (BYOK), kept in Keychain.
One literal word across a 10 GB log in 3.14 s. Click a result and that line opens; Shift-JIS and EUC-JP files are detected per file.
Everything for reading is in the free MrEditor (MIT licensed).
Open, narrow, fix, save without breaking.
Free
Free forever · signed and notarized
MIT License · Source on GitHub
Stop guessing where to look.
$19
One-time · up to 2 Macs per license
| MrEditor | MrkEditor | |
|---|---|---|
| Open, search, edit and save huge files | ✓ | ✓ |
| Structured view and JSON queries | ✓ | ✓ |
| Compare and merge | ✓ | ✓ |
| Remote logs over SSH and follow mode | ✓ | ✓ |
| AI error root causes (BYOK) | ✓ | ✓ |
| Value aggregation | — | ✓ |
| Time distribution | — | ✓ |
| Column statistics for CSV | — | ✓ |
| Search across folders | — | ✓ |
| Price | Free | $19 one-time |
MrkEditor has no separate trial. The free MrEditor is the same editor core, so you can try it on your real files first. If it fits, add MrkEditor with a one-time purchase.
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