Text Filters

Text filters match against the raw content of each log line.

Adding Filters

From normal mode:

Press i to add an include filter (opens command mode pre-filled with filter )
Press o to add an exclude filter (opens command mode pre-filled with exclude )

From command mode:

:filter <pattern>       # show only lines matching pattern
:exclude <pattern>      # hide lines matching pattern

Pattern Matching

logana automatically selects the fastest matching strategy based on your pattern:

Literal matching (default) — used when the pattern contains no regex metacharacters. Uses Aho-Corasick for O(n) multi-pattern scanning. Case-sensitive.

Regex matching — activated automatically when the pattern contains any of: . * + ? ( ) [ ] { } ^ $ | \. Uses the regex crate.

Examples:

:filter ERROR               # literal — fast
:filter "connection refused"  # literal with spaces
:filter "ERR(OR)?"          # regex — matches ERR or ERROR
:filter "\d{3} \d+"         # regex — HTTP status + bytes
:filter "^2024-"            # regex — lines starting with date

Multiple Filters

You can add as many filters as you like. They combine as follows:

Include filters — a line must match at least one enabled include filter to be shown (if any exist).
Exclude filters — a line matching any enabled exclude filter is hidden.

Exclude takes priority: a line that satisfies an include filter but also matches an exclude filter is hidden.

Toggling Filters

In the filter manager (f), press Space to enable/disable individual filters.
Press F in normal mode to toggle all filtering on/off instantly (useful for comparing filtered vs. unfiltered view).
Press A in the filter manager to enable/disable all filters at once.

Highlight Colors

Each include filter highlights its matching byte spans in the log line. The color is configurable per filter. When no color is set, logana uses a default highlight style from the active theme.

To set a color for the currently selected filter in the filter manager, press c, then use :set-color:

:set-color --fg yellow
:set-color --fg "#FF5555" --bg "#44475A"

By default, only the matched portion of the line is colored (match_only = true). To highlight the entire line instead, use the -l flag when adding the filter (not yet exposed via UI — set via :set-color after adding).

When multiple filters overlap on the same span, their fg and bg are composed: one filter can contribute the foreground color while another contributes the background. Automatic value colors (HTTP methods, status codes, IPs, UUIDs) apply only to spans not already colored by a filter, and log-level colors are the lowest-priority fallback.

Editing Filters

Editing a filter’s pattern or color from the filter manager (e to edit pattern, c to change color) updates it in-place. The filter keeps its current position in the list — order is never changed by an edit.

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