Filtering

Filters are the primary way to narrow the log view. They are layered: include patterns narrow the view, and exclude patterns hide matching lines on top of whatever include filters already selected.

Quick Keys

Key	Action
`i`	Add include filter (show only matching lines)
`o`	Add exclude filter (hide matching lines)
`f`	Open filter manager
`F`	Toggle all filtering on/off

How Filters Work

Include filters: If any include filter is enabled, only lines matching at least one include filter are shown.

Exclude filters: Any line matching an enabled exclude filter is hidden, regardless of include filters.

No filters: All lines are shown.

Both filter types support:

Literal strings — fast multi-pattern matching via Aho-Corasick
Regular expressions — full regex syntax via the regex crate (activated automatically when the pattern contains metacharacters)

Filters are saved to SQLite and automatically restored the next time you open the same file. When you reopen a file, logana detects whether the file has changed (via hash) and prompts you to restore the previous session.

Filter Manager

Press f to open the filter manager popup, which lists all active filters.

Key	Action
`j` / `k`	Navigate filters
`Space`	Toggle selected filter on/off
`e`	Edit selected filter’s pattern
`d`	Delete selected filter
`c`	Set highlight color for selected filter
`t`	Add a date/time range filter
`J` / `K`	Move filter down / up (order affects priority)
`A`	Toggle all filters on/off
`C`	Clear all filters
`Esc`	Close filter manager

Filter Colors

Each filter can have an optional highlight color. When a filter matches part of a line, that part is colored using the filter’s configured color. Colors are set per-filter with c in the filter manager, or via the :set-color command.

:set-color --fg red
:set-color --fg "#FF5555" --bg "#282A36"

Color values accept:

Named colors: black, red, green, yellow, blue, magenta, cyan, white, gray, darkgray, lightred, lightgreen, lightyellow, lightblue, lightmagenta, lightcyan
Hex: "#RRGGBB"

Style composition

When multiple filters overlap on the same text segment, their fg and bg attributes are composed independently — the highest-priority filter that has fg set contributes the foreground color, and the highest-priority filter that has bg set contributes the background color. So a level filter that sets --fg yellow and a text filter that sets --bg darkgray on the same word will both apply without one canceling the other.

Color priority

Filter colors take priority over automatic value colors (HTTP methods, status codes, IPs, UUIDs) and log-level colors. Value colors are applied only to spans that are not already covered by a filter — they can still appear alongside filter colors on the same line, just not on the same character span. Log-level colors are the lowest-priority fallback and apply only to text that carries no explicit color from any other source.

Save and Load Filters

Export the current filter set to a JSON file, and reload it later:

:save-filters my-filters.json
:load-filters my-filters.json

This is useful for sharing filter sets across machines or between log files with similar structure.

Inline Filters at Startup

Add filters directly on the command line without creating a JSON file first:

Flag	Short	Purpose
`--include <args>`	`-i`	Add include filter
`--exclude <args>`	`-o`	Add exclude filter
`--timestamp <args>`	`-t`	Add date/time range filter

The argument string passed to each flag accepts exactly the same options as the corresponding TUI command (:filter, :exclude, :date-filter):

# Simple pattern
logana app.log -i error -o debug

# Field-scoped filter
logana app.log -i "--field level=ERROR"

# Include filter with highlight color
logana app.log -i "--bg Red error"

# Date range filter
logana app.log -t "> 2024-02-21"

# Combined
logana app.log -i error -o debug -t "01:00 .. 02:00"

All flags can be repeated. Inline filters are applied after any --filters file. Invalid argument strings are rejected before the TUI opens.

Preloading Filters at Startup

Pass --filters (or -f) on the command line to apply a saved filter set before the TUI opens:

logana app.log --filters my-filters.json

The filters are evaluated in a single pass during file indexing, so the filtered view is ready as soon as loading completes — no separate computation step. The same filters remain active for interactive use once the TUI is open (you can add, remove, or edit them normally).

Combined with --tail, the last matching line is shown immediately after loading:

logana app.log --filters errors.json --tail

Tip: Save your most-used filter sets with :save-filters once, then reuse them from the command line.

Sections

Text Filters — include/exclude patterns, regex syntax
Date & Time Filters — timestamp-based range and comparison filters
Field Filters — match against specific parsed fields (level, message, component, …)

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