nothing-less 1.4.0

A TUI paging application with enhanced support for tabular data and real-time streaming

Nothing-less (nless)

Nless is a TUI paging application (based on the awesome Textual library) with vi-like keybindings.

Read the full documentation — tutorials, keybinding reference, configuration, and more.

Nless has enhanced functionality for parsing tabular data:

• inferring file delimiters
• delimiter swapping on the fly
• regex-based parsing of raw logs into tabular data using Python's regex engine
• filtering
• sorting
• searching
• real-time event parsing.

Getting started

Dependencies

• python>=3.13 OR
• brew

Installation

pip install nothing-less OR brew install mpryor/tap/nless

Usage

• pipe the output of a command to nless to parse the output $COMMAND | nless
• read a file with nless nless $FILE_NAME
• redirect a file into nless nless < $FILE_NAME
• Once output is loaded, press ? to view the keybindings

Demos

Basic functionality

The below demo shows basic functionality:

• starting with a search /
• applying that search &
• filtering the selected column by the value within the selected cell F
• swapping the delimiter D (raw and ,)

Streaming functionality

The below demo showcases some of nless's features for handling streaming input, and interacting with unknown delimitation:

• The nless view stays up-to-date as new log lines arrive on stdin (allows pipeline commands, or redirecting a file into nless)
• Showcases using a custom (Python engine) regex, example - {(?P<severity>.*)}\((?P<user>.*)\) - (?P<message>.*) - to parse raw logs into tabular fields.
• Sorts, filters, and searches on those fields.
• Flips the delimiter back to raw, sorts, searches, and filters on the raw logs

Why nless?

As a kubernetes engineer, I frequently need to interact with streaming tabular data. k get pods -w, k get events -w, etc. I wanted a TUI tool to quickly dissect and analyze this data - and none of the existing alternatives had exactly what I wanted. So I decided to build my own tool, integrating some of my favorite features from other similar tools.

This project is not meant to replace any of the tools mentioned in the alternatives section. Instead, it's meant to bring its own unique set of features to complement your workflow:

• Streaming support - stay up-to-date as new data arrives on stdin, with arrival timestamps and time window filtering
• Delimiter inference - no configuration needed; nless infers the delimiter from your data and auto-switches on mismatch
• Vi-like keybindings - familiar to any Vim user, minimize keypresses to analyze a dataset
• Kubernetes-friendly - built for K8s use-cases like parsing streams from kubectl
• Tabular data toolkit - filter, sort, search, pivot, and reshape data on the fly
• JSON & log parsing - convert unstructured data streams into tabular data

Features

• Buffers - mutating actions create a new buffer, letting you jump up and down your analysis history
• Delimiter swapping - swap between CSV, TSV, space-aligned, JSON, regex with named capture groups, and raw mode on the fly with D
• Column delimiters - split a column into more columns using JSON, regex, or string delimiters with d
• Filtering - filter by column (f/F), exclude (e/E), across all columns (|), or from a search (&)
• Sorting - toggle ascending/descending sort on any column with s
• Searching - search (/), search by cell value (*), navigate matches (n/p)
• Pivoting - group records by composite key with U, focused summary view, dive into grouped data with enter
• Column management - show/hide columns (C), reorder columns (</>)
• JSON extraction - promote nested JSON fields to columns with J
• Shell commands - run a shell command and pipe its output into a new buffer with !
• Tail mode - keep the cursor at the bottom as new data arrives with t
• Output - write buffer contents to a file or stdout (W), copy cell values (y)
• Themes - 10 built-in color themes (Dracula, Nord, Gruvbox, etc.) plus custom theme support, switch with T
• Arrival timestamps - every row records when it was received; toggle the _arrival column with A
• Time window filtering - show only recent rows with @ (e.g. 5m, 1h); append + for rolling windows
• Excluded lines - view lines that failed to parse or were removed by filters with ~, with chained accumulation across buffers

Full keybinding reference

Buffers:

• [1-9] - select the buffer at the corresponding index
• L - select the next buffer
• H - select the previous buffer
• q - close the current active buffer, or the program if all buffers are closed
• N - create a new buffer from the original data
• r - rename the current buffer

Groups:

• } - switch to the next buffer group
• { - switch to the previous buffer group
• R - rename the current group
• O - open a file in a new buffer group

Navigation:

• h - move cursor left
• l - move cursor right
• j - move cursor down
• k - move cursor up
• 0 - jump to first column
• $ - jump to final column
• g - jump to first row
• G - jump to final row
• w - move cursor right
• b/B - move cursor left
• ctrl+u - page up
• ctrl+d - page down
• c - select a column to jump the cursor to

Column visibility:

• C - prompt for a regex filter to selectively display columns, or all to see all columns
• > - move the current column one to the right
• < - move the current column one to the left
• A - toggle the _arrival metadata column showing when each row was received

Pivoting:

• U - mark the selected column as part of a composite key to group records by, adding a count column pinned to the left
• enter - while over a composite key column, dive into the data behind the pivot

Filtering:

• f - filter the current column and prompt for a filter
• F - filter the current column by the highlighted cell
• e - exclude from the current column and prompt for a value
• E - exclude the current column by the highlighted cell
• | - filter ALL columns and prompt for a filter
• & - apply the current search as a filter across all columns
• @ - set a time window to show only recent rows (e.g. 5m, 1h); append + for rolling

Searching:

• / - prompt for a search value and jump to the first match
• * - search all columns for the current highlighted cell value
• n - jump to the next match
• p - jump to previous match

Output:

• W - prompt for a file to write the current buffer to (- writes to stdout)
• y - copy the contents of the currently highlighted cell to the clipboard

Shell Commands:

• ! - run a shell command and pipe its output into a new buffer

Tail Mode:

• t - toggle tail mode
• x - reset new-line highlights

Themes & Keymaps:

• T - open the theme selector
• K - open the keymap selector

Excluded Lines:

• ~ - view excluded lines (parse failures + filtered rows), with chained accumulation

Sorting:

• s - toggle ascending/descending sort on the current column

JSON:

• J - select a JSON field under the current cell to add as a column

Delimiter/file parsing:

• D - swap the delimiter on the fly (common delimiters, regex with named capture groups, raw, json, or for double-space aligned output like kubectl)
• d - split a column into more columns using a columnar delimiter (json, regex with named capture groups, or any string)

Help:

• ? - show the help screen with all keybindings

See the full keybinding reference and tutorials for more.

Contributing

Contributions are welcome! Please open an issue or a pull request - check out the contributing guidelines for more information.

Alternatives

Shout-outs to all of the below wonderful tools! If my tool doesn't have what you need, they likely will:

• visidata
• csvlens
• lnav
• toolong