A while back I published a feature-comparison table between my large-file text viewer UwView and the industry-standard log viewer klogg. One rule: list every row I'm losing on, too. That table reflected the free version (UVF) at v1.0.0. Since then, v1.1 → v1.1.1 filled in a number of those "losing" rows, so here's the complete edition as of v1.1.1 — three columns (klogg, free UwView (UVF), and paid UwView Pro (UVP)), same items, status brought up to date. I still don't hide the rows where klogg wins.
Legend: ✅ = yes / 🔶 = partial or limited / ❌ = no (planned) / — = not applicable. Baseline: klogg 24.11.0, UVF v1.1.1, and an internal UVP build.
1. Performance & core (where UwView leads)
| Feature | klogg | UVF 1.1.1 | UVP 1.1.1 |
|---|---|---|---|
| Instant open of huge files (browse the whole file before indexing finishes) | ❌ Head only until indexing completes | ✅ Instant page-mode display | ✅ Same |
| Persistent index (reopening is instant) | ❌ Re-indexes every time | ❌ Rebuilds every time | ✅ .uwvz (from a few ms) |
| Fast search via compressed cache | ❌ | ❌ | ✅ (3–9× vs klogg, measured) |
| Archive workflow (delete original, keep ~1/9 size) | ❌ | ❌ | ✅ Checksum-protected |
| Automatic Japanese encoding detection (Shift-JIS/EUC-JP) | ❌ Manual | ✅ Auto + manual switch | ✅ |
| Largest scale verified | ~1B lines (claimed) | 892M lines / 51 GB (measured) | Same |
| Browser (WASM) build | ❌ | ✅ (bonus) | — |
| JA/EN UI switch | ❌ English only | ✅ | ✅ |
Opening a huge file and moving freely through the whole thing right away is clearly where UVF/UVP lead, and Pro is another order of magnitude ahead on reopening, search, and storage size (see the measured 3-size benchmark).
2. Search, filtering & color coding (big progress in v1.1 / v1.1.1)
| Feature | klogg | UVF 1.1.1 | UVP 1.1.1 |
|---|---|---|---|
| Regex search | ✅ | ✅ literal/regex | ✅ + fast icase path |
| Results in a separate view + jump to text | ✅ Bottom pane | ✅ Popup (auto-shown) | ✅ Per tab |
| Context lines around results (±N) | ❌ | ✅ ±1 | ✅ ±1000 |
| Save results to a separate file (with original line numbers) | ❌ | ✅ | ✅ |
| Match highlight + minimap distribution | 🔶 Emphasis only | ✅ Minimap + click-to-jump | ✅ |
| Multi-keyword color highlighter | ✅ | ✅ v1.1 (32 colors, regex capture groups, 7 bundled presets, .uwvhl import/export, per tab) |
✅ Same |
| Right-click instant coloring of a selected word | ✅ | ✅ v1.1.1 (right-click → color, 3-tier word selection) | ✅ |
| Saved predefined filters / search history | ✅ | ✅ v1.1 (50-entry history, ★ save) | ✅ |
| In-view incremental search (QuickFind, Ctrl+F) | ✅ | 🔶 Mostly covered by next/previous | 🔶 Same |
| Boolean search expressions (AND/OR) | 🔶 via regex | ❌ | ❌ |
The "log-analysis toolbox" — color highlighting, search history, quick coloring — where klogg had the edge in v1.0 is now almost entirely filled in. Bundled presets went from 5 (v1.1) to 7 after adding GeoJSON / KML in v1.1.1. QuickFind isn't implemented yet, but next/previous (< >) covers most of the need, so it's low priority.
3. Display & operation
| Feature | klogg | UVF 1.1.1 | UVP 1.1.1 |
|---|---|---|---|
| Multi-file tabs | ✅ | ✅ Drag & drop / multi-select | ✅ |
| Bookmarks (marks) | ✅ | ✅ Toggle / prev-next / minimap | ✅ |
| Line selection (drag) → copy/save | 🔶 | ✅ v1.1 | ✅ |
| Rectangular (column) selection & copy | ❌ | ❌ | ✅ v1.1 (Pro only) |
| Line-number display | ✅ | ✅ | ✅ |
| Scratchpad (base64/JSON/XML formatting workspace) | ✅ | ❌ → planned | ❌ |
| Line-wrap display | ✅ | ❌ → planned | ❌ |
4. Monitoring (tail) & operations (klogg's remaining strengths)
| Feature | klogg | UVF 1.1.1 | UVP 1.1.1 |
|---|---|---|---|
Follow appended writes (tail -f equivalent) |
✅ Follow mode | ✅ Incremental index + auto-scroll | ✅ |
| Session restore (reopen the previous set of files) | ✅ | ✅ v1.1.1 (near previous scroll position) | ✅ v1.1.1 |
| Recent files, favorites, start screen | ✅ Recently used | ✅ v1.1.1 (last 15, ★ favorites) | ✅ |
| Auto-updating search results while following | ✅ | ❌ → planned (high priority) | ❌ |
| Per-file state restore (marks, encoding, Follow) | ✅ | ❌ → planned (per-file) | 🔶 Index persistent; marks etc. ❌ |
| Log rotation / truncation handling | 🔶 | ❌ | ❌ |
Around "resuming your work," v1.1.1's session restore, recent files, and favorites filled in most of the gap. What remains is auto-updating search tied to Follow and fine-grained per-file state restore.
5. Distribution & ecosystem (where klogg's overall strength counts)
| Item | klogg | UVF 1.1.1 | UVP 1.1.1 |
|---|---|---|---|
| Price / license | Free, GPL (OSS) | Free, PolyForm Internal Use (source available) | Paid (commercial, on sale) |
| Supported OS | Win/Mac/Linux | Win/Mac/Linux + WASM | Win/Mac/Linux |
| Package distribution (Homebrew/Chocolatey/winget…) | ✅ Extensive | 🔶 GitHub Releases / Vector | 🔶 Polar |
| OS shell integration / portable build | ✅ (Windows) | ❌ → planned | ❌ |
| Track record / user base | ✅ 10+ years in the glogg lineage | 🔶 Still building | 🔶 |
| Encoding coverage (Chinese, Korean, Cyrillic…) | ✅ Broad (Qt base) | 🔶 UTF-8/Shift-JIS/EUC-JP/UTF-16 → planned | 🔶 |
Distribution, track record, and encoding breadth are where klogg is still clearly ahead. Those don't get filled in overnight, so I'm leaving them exactly as they are — honestly.
Rows filled in vs. still remaining (v1.0 → v1.1.1)
- Filled in (klogg's edge → UVF now ✅ too): multi-keyword color highlighter, right-click instant coloring, search history / predefined filters, line selection → copy/save, session restore, recent files / favorites.
- Still remaining (klogg still ahead): auto-updating search while following, per-file state restore, QuickFind (substitutable with next/previous), Boolean search, Scratchpad, line-wrap, package distribution / shell integration, track record / encoding breadth.
I don't hide the remaining items — they're all listed openly in the GitHub roadmap issue. I'll work through them top-down, not by copying klogg outright, but by designing each in whatever shape I find easiest to use myself.
Bottom line
- Performance and the huge-file experience remain UVF/UVP's strength. Pro takes it another order of magnitude further (persistent index, compressed search, 1/9 storage).
- The log-analysis toolbox gained color highlighting, quick coloring, search history, and restore features in v1.1/v1.1.1 — closing the gap with klogg considerably.
- klogg's remaining advantages: Follow-linked search, per-file state restore, distribution, track record. All on the public roadmap.
- If your work is routine log analysis and you value distribution and track record, klogg is still a solid choice. If you want to open and read huge files fast, auto-detect Japanese log encodings, and track things by color, give UwView a try — it's free.
- And if a huge log is eating your disk and you want it compressed for storage while staying searchable at speed, give UwView Pro a look — persistent index, compressed-cache search, and ~1/9 storage make both reopening and searching a step faster (all OS, $129 one-time / $9 per month).
Not a "klogg killer" — different tools for different jobs. I respect klogg and compare against it honestly.
- Full write-up (original): https://uvp.y42u.net/en/blog/uwview-klogg-feature-comparison-v111-en/
- UwView Pro ($129 one-time / $9 per month): https://uvp.y42u.net/en/pro-en/
- Source / roadmap: https://github.com/amru195704/UwView
- Browser demo (no install): https://amru195704.github.io/UwView/
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