A terminal-based log processing and data visualization tool that displays real-time histograms of tabular data.

• Processes tabular data from stdin in real-time
• Creates histograms of numeric values
• Supports faceting (grouping) by columns
• Interactive navigation between facets
• Pinning feature to filter data by specific facet values
• Displays statistics (mean, standard deviation, count)
• Colorized visualization with dynamic scaling
• Smooth scrolling and window resizing

Example: real-time log analysis of fly.io logs.

flyctl logs --json \
  | jq '.message |= fromjson' -r \
  | jq 'select(.message.payload.duration_ms != null) | [.message.payload.duration_ms, .message.payload.url, .region, .instance] | @tsv' -r \
  | histo

View histograms of across values within a facet.

Pinning a value within a facet applies it as a filter to the stream. For example, pinning the endpoint allows us to view request duration statistics for just that endpoint.

• a/d: Change facet column
• ←→↑↓: Navigate between facets
• Enter: Pin/unpin a facet (filters data to only show entries matching that facet)
• 0: Show all facets
• j/k: Scroll content
• q/Ctrl+C: Quit

Histo expects tab-separated values (TSV) where:

• First column contains the numeric values to plot
• Subsequent columns define facets

Example:

10.5    red    seattle
15.2    red    san jose
8.7     blue    seattle
12.1    blue    san jose

go build

• Bubble Tea - Terminal UI framework
• Lip Gloss - Style definitions for terminal applications

MIT - see LICENSE file for details.