Cascade

A log analyzer for files that don't fit in memory, with filters that nest.

A from-scratch reimagining of TextAnalysisTool.NET for Windows.

Download · Filters · Reading the log · Fields · Files · Settings · Keyboard

---

Filters

What a filter is

• Matches a substring, a .NET regular expression, or marked by marker 1–8.
• A line is shown when an enabled include matches it and no enabled exclude does.
• Colour, background, bold, italic and underline are each on, off, or inherited.

Nesting

• A child narrows its parent: [ERROR] → payment-svc means errors, in payments only.
• A child matches a line only if every one of its ancestors matches it too — whether or not those ancestors are switched on.
• So switching a parent off does not stop it narrowing its children: you can scope a branch without showing everything the parent matches.
• A line takes its colour from the first filter in the list that matched it, refined by whichever of that filter's own descendants matched too — never by a filter in a branch further down, however deeply nested.
• Whatever the winning filter leaves unset it inherits from the filters above it, so a filter with no colour of its own draws the line in the view's default colours.
• Nest with Alt+→, or by dragging.

The filter list

• Count is how many lines in the whole file match, not how many are on screen.
• Shift+Space switches a filter's whole subtree on or off.
• The list docks to any edge of the window, or hides altogether (Ctrl+Shift+L).

From the log to a filter

• Ctrl+N turns the text you have selected inside a line — or the whole line under the caret — into a filter.

Colour

• I'm feeling lucky picks a legible colour pair that no other filter is using; Paint chips… shows the rest of the palette.
• A filter with no colour of its own leaves no mark on the match map.

Working on many at once

• Select several filters and enable, disable, delete, duplicate, reorder, nest or recolour them in one go.
• Dragging carries the whole selection, nesting and all.
• Ctrl+Z undoes filter edits, drags included.

Finding a filter among hundreds

• Ctrl+E searches the list without hiding or reordering it — non-matching filters dim rather than disappear.
• F4 / Shift+F4 walk the log through the selected filter's matches, without changing which filters are on.

Presets

• A preset names a combination of filters — the payment incident, the slow queries.
• The tick applies a preset; the highlight only says which one the commands act on.
• Ticking two gives you both, and ticking one moves only its own filters — anything you switched on by hand stays as you left it.

Dim or hide

• Ctrl+H switches between dimming the lines that didn't match and hiding them altogether.
• Line numbers are always the file's own, either way.

---

Reading the log

Find

• Ctrl+F searches the text, literal or regex, marking every occurrence on screen as you type.
• Find works on every line, not just the shown ones: hits on hidden lines are counted separately, and it says so when a match lands on one.

The match map

• The scrollbar is replaced by the whole file at a pixel a line, in the colours the filters gave it.
• Unmatched stretches are compressed, so one error among ten thousand ordinary lines still gets a pixel of its own.

Markers

• Eight colours for marking lines by hand: Ctrl+1…Ctrl+8 on the selection.
• The bare number keys 1…8 then walk between the lines you marked, Shift to go backwards.
• Marked by marker N is a filter type, so lines you picked out by hand can be treated as a category.

What matched this line

• Hovering a line names every filter that matched it — including the ones that are switched off.

Getting lines out

• File ▸ Save Current Lines… writes out exactly what the filters are showing.
• Edit ▸ Copy with Line Numbers copies the file's own line numbers along with the text.

---

Fields

Long lines are either wrapped (Alt+Z) or split into fields you can hide and reorder.

Splitting a line

• Ctrl+Shift+C splits every line into fields for display, guessing a template from the line under the caret.
• Filtering and searching always run on the whole raw line, so this can shorten a line but never hide one.
• A line the template does not match is left whole and untouched.

The template

A template is a picture of your line: write one out, replace what changes with *, and wrap each field in { }.

your line:  [2026-08-05T05:00:02][BthPort][INFO] WDF PnP state: started
template:   {[*]}{[*]}{[*]} {*}

*	the text that changes — matches as little as it can, up to whatever you wrote next
{ }	one field: the unit that gets hidden or moved, punctuation and all
anything else	has to be there, except a run of spaces, which matches any run of spaces
\	makes { } * \ ordinary

• Punctuation goes with the field, so hiding the middle of [a][b][c] leaves [a][c] rather than [a][][c].

Columns and Inline

• Columns lays the fields out as a table: drag a header to reorder, double-click it to rename, right-click for the list of which fields are shown.

• Inline keeps every row a line and leaves out what you hid — better when one field dwarfs the rest.
• A strip of chips stands in for the header: click one to put a field away or bring it back, drag it to move the field along the row.

Field settings

• Ctrl+Shift+D tries the template against real lines from the file: how many of them match, and where a line that doesn't stopped matching.
• Detect writes the template for you when the line begins with bracketed groups: [ ], ( ) or < >.

---

Files

Opening

• Drop a log on the window, hand it to Cascade.exe on the command line, or use Open from Clipboard for one you have pasted from somewhere else.
• F5 re-reads the file, for when you have just re-run whatever produced it.
• Dropping a .cascade or .tat file loads its filters instead of opening it as a log.
• The file is memory-mapped and indexed as it streams, four bytes a line: a 1 GB, 10-million-line log is on screen in milliseconds and fully indexed in under half a second.

Encodings

• A byte-order mark is honoured; without one, UTF-8 is assumed.
• View ▸ Encoding reads the file again as UTF-16 or UTF-32 (either endianness), Windows-1252 or the system code page.

Filter files

• .cascade is JSON — the filter tree with its styles, the presets, and the field template — so a filter set diffs well in source control.
• Ctrl+S saves the set you have; File ▸ Append Filters… merges another set into it.
• TextAnalysisTool.NET .tat files are imported, flattened to top-level filters. Saving is always .cascade.

---

Settings

Preferences

• File ▸ Settings ▸ Export / Import moves your preferences to another machine.

Where things live

• Preferences in %APPDATA%\Cascade\settings.json, machine-local state in state.json, and nothing at all in the registry. CASCADE_SETTINGS_DIR moves the folder.

Command line

Cascade.exe [file] [/Filters:<path>]

• /Filters: also stops the last-used filter file being loaded automatically.
• CASCADE_UPDATE=off turns off the update check.

---

Install

Download Cascade.exe and run it — a single file, no installer.

curl.exe -fL --remove-on-error -o Cascade.exe https://github.com/rahul-ramadas/Cascade/releases/latest/download/Cascade.exe

• Needs Windows and the .NET 10 Desktop Runtime. It updates itself.
• Draws with GDI rather than a GPU, so it stays quick over a remote desktop.

---

Keyboard reference

Log view

Key	Action
↑ ↓ PgUp PgDn	Move the caret (Shift extends the selection)
Ctrl+Home / Ctrl+End	First / last line
Ctrl+↑ / Ctrl+↓	Scroll a line without moving the caret
← → / Home End	Scroll sideways / to the far left and right
Drag, double-click, triple-click	Select part of a line, a word, the whole line
Ctrl+A / Ctrl+C	Select all / copy
1…8 / Shift+1…8	Next / previous line with that marker
Ctrl+1…Ctrl+8	Toggle that marker on the selection
Ctrl+wheel	Zoom

Filter list

Key	Action
Space / Shift+Space	Enable or disable the selection / their subtrees
Enter / Delete / Ctrl+D	Edit / remove / duplicate the selection
Shift+↑ ↓ / Ctrl+↑ ↓ / Ctrl+Space / Ctrl+A	Extend, move through, add to, or take the whole selection
Alt+↑ ↓ ← →	Move, nest and un-nest
F4 / Shift+F4	Next / previous line matching the current filter
Ctrl+E, then Enter / Shift+Enter / F3	Search the list and walk the matches
Double-click a filter / the empty space below	Edit it / add a new one

Global

Key	Action
Ctrl+O / F5 / Ctrl+S	Open / reload / save filters
Ctrl+Z / Ctrl+Y	Undo / redo a filter edit
Ctrl+F / F3 / Shift+F3	Find / next / previous
Ctrl+G / Ctrl+H	Go to line / show only filtered lines
Ctrl+N	New filter from the selection or the current line
Ctrl+E	Search the filter list
Ctrl+M / Alt+Z / Ctrl+Shift+C	Match map or plain scrollbar / word wrap / split lines into fields
Ctrl+Shift+X / Ctrl+Shift+D	Switch field layout / field settings
Ctrl+Shift+P / Ctrl+Shift+L	Show or hide the presets pane / the filter list
Ctrl+Shift+T / Ctrl+Shift+F	Focus the log view / the filter list
Ctrl+Shift+↑ ↓ ← →	Dock the filter list
Ctrl++ / Ctrl+- / Ctrl+0	Zoom in / out / reset
Tab	Move between the log and the filter list
Esc	Stop a search, then close the bar and clear its marks

---

Building

dotnet build Cascade.slnx -c Release
dotnet test tests/Cascade.Core.Tests/Cascade.Core.Tests.csproj   # engine tests
./scripts/Run-UiTests.ps1 -Publish                               # UI automation, off-screen
./scripts/Build-DocImages.ps1                                    # every picture above, from the app

• .NET 10 SDK. src/Cascade.Core is the UI-agnostic engine — indexing, filtering, find, markers, columns, persistence — and src/Cascade.App is the WinForms GUI.

License

MIT © 2026 Rahul Ramadas.