Note: ⚠️ As of version 2.0.0, moar has been renamed to moor, but is otherwise the same tool.

Moor is a pager. It reads and displays UTF-8 encoded text from files or pipes.

moor is designed to just do the right thing without any configuration:

The intention is that Moor should be trivial to get into if you have previously been using Less. If you come from Less and find Moor confusing or hard to migrate to, please report it!

Doing the right thing includes:

• Syntax highlight source code by default using Chroma
• Search is incremental / find-as-you-type just like in Chrome or Emacs
• Filtering is incremental: Press & to filter the input interactively
• Search becomes case sensitive if you add any UPPER CASE characters to your search terms, just like in Emacs
• Regexp search if your search string is a valid regexp
• Deduplicated search history persists across moor invocations
• Snappy UI even on slow / large input by reading input in the background and using multi-threaded search
• Supports displaying ANSI color coded texts (like the output from git diff | riff for example)
• Supports UTF-8 input and output
• Transparent decompression when viewing compressed text files (.gz, .bz2, .xz, .zst, .zstd) or streams
• The position in the file is always shown
• Supports word wrapping (on actual word boundaries) if requested using --wrap or by pressing w
• Follows output as long as you are on the last line, just like tail -f
• Renders terminal hyperlinks properly
• Mouse Scrolling works out of the box (but look here for tradeoffs)

For compatibility reasons, moor uses the formats declared in these environment variables if present:

• LESS_TERMCAP_md: Man page bold
• LESS_TERMCAP_us: Man page underline
• LESS_TERMCAP_so: Status bar and search hits

Setting LESSSECURE to 1 will prevent moor from launching external programs or opening new files as required by systemctl(1). In secure mode, the v command for opening the current file in an editor is disabled.

For configurability reasons, moor reads extra command line options from the MOOR environment variable.

Moor is used as the default pager by:

• px / ptop, ps and top for human beings
• riff, a diff filter highlighting which line parts have changed

Installing

Using Homebrew

Both macOS and Linux users can use Homebrew to install. See below for distro specific instructions.

Then whenever you want to upgrade to the latest release:

Using Debian

On Debian Forky and newer, as well as on Ubuntu 26.04 Resolute and newer:

Using MacPorts

More info here.

Using Gentoo

emerge --ask --verbose sys-apps/moor

More info here.

Using Arch Linux

More info here.

Manual Install

Using go

This will install moor into $GOPATH/bin :

go install github.com/walles/moor/v2/cmd/moor@latest

NOTE: If you got here because there is no binary for your platform, please consider packaging moor.

Downloading binaries

1. Download moor for your platform from https://github.com/walles/moor/releases/latest
2. chmod a+x moor-*-*-*
3. sudo mv moor-*-*-* /usr/local/bin/moor

And now you can just invoke moor from the prompt!

Try moor --help to see options.

Configuring

Do moor --help for an up to date list of options.

Environment variable MOOR can be used to set default options.

For example:

export MOOR='--statusbar=bold --no-linenumbers'

Setting moor as your default pager

Set it as your default pager by adding...

export PAGER=/usr/local/bin/moor

... to your .bashrc.

Issues

Issues are tracked here, or you can send questions to johan.walles@gmail.com.

Packaging

If you package moor, do include the man page in your package.

Comparison with bat

moor and bat do different things. moor is a pager. bat is a file preprocessor that sometimes pipes to a pager (like moor). So comparing them directly is not possible.

What bat does is:

1. Looks at its input and preprocesses it or not
2. Pipes to a pager or not. This pager can be moor or something else.

Some of bat's preprocessing overlaps with what moor provides internally (like syntax highlighting and JSON formatting).

But some moor features like fast interactive search is moor specific and not something bat can simulate through preprocessing.

To use moor as your bat pager, set BAT_PAGER=moor in your environment.

Or, to use moor instead of bat, set PAGER=moor.

Embedding moor in your app

API Reference: https://pkg.go.dev/github.com/walles/moor/v2/pkg/moor

For a quick start, first fetch your dependency:

go get github.com/walles/moor/v2

Then, here's how you can use the API:

package main

import (
	"github.com/walles/moor/v2/pkg/moor"
)

func main() {
	err := moor.PageFromString("Hello, world!", moor.Options{})
	if err != nil {
		// Handle paging problems
		panic(err)
	}
}

After both go get is done and you have calls to moor in your code, you may have to:

You can also PageFromStream() or PageFromFile().

Developing

You need the go tools.

Run tests:

Launch the manual test suite:

To run tests in 32 bit mode, either do GOARCH=386 ./test.sh if you're on Linux, or docker build . -f Dockerfile-test-386 (tested on macOS).

Run microbenchmarks:

go test -benchmem -run='^$' -bench=. ./...

Profiling BenchmarkPlainTextSearch(). Try replacing -alloc_objects with -alloc_space or change the -focus function:

go test -memprofilerate=1 -memprofile=profile.out -benchmem -run='^$' -bench '^BenchmarkPlainTextSearch$' ./internal && go tool pprof -alloc_objects -focus findFirstHit -relative_percentages -web profile.out

Or to get a CPU profile:

go test -cpuprofile=profile.out -benchmem -run='^$' -bench '^BenchmarkRenderLines$' ./internal && go tool pprof -focus renderLines -relative_percentages -web profile.out

Build + run:

Install (into /usr/local/bin) from source:

Making a new Release

Make sure that screenshot.png matches moor's current UI. If it doesn't, scale a window to 81x16 characters and make a new one.

Execute release.sh and follow instructions.

TODO

• Enable exiting using ^c (without restoring the screen).

• Enable suspending using ^z, followed by resuming using fg.

• Underline the file name in the status bar while viewing. The point is to make it more obvious where this name ends in case it contains whitespace.

• Retain the search string when pressing / to search a second time.

Done

• Add > markers at the end of lines being cut because they are too long

• Doing moor on an arbitrary binary (like /bin/ls) should put all line-continuation markers at the rightmost column. This really means our truncation code must work even with things like tabs and various control characters.

• Make sure search hits are highlighted even when we have to scroll right to see them

• Change out-of-file visualization to writing --- after the end of the file and leaving the rest of the screen blank.

• Exit search on pressing up / down / pageup / pagedown keys and scroll. I attempted to do that spontaneously, so it's probably a good idea.

• Remedy all FIXMEs in this README file

• Release the go version as the new moor, replacing the previous Ruby implementation

• Add licensing information (same as for the Ruby branch)

• Make sure git grep output gets highlighted properly.

• Handle all kinds of line endings.

• Make sure version information is printed if there are warnings.

• Add spinners while file is still loading

• Make tail -f /dev/null exit properly, fix #7.

• Showing unicode search hits should highlight the correct chars

• Word wrap text rather than character wrap it.

• Arrow keys up / down while in line wrapping mode should scroll by screen line, not by input file line.

• Define 'g' to prompt for a line number to go to.

• Handle search hits to the right of the right screen edge when searching forwards. Searching forwards now moves first right, then to the left edge and down.

• Handle search hits to the right of the right screen edge when searching backwards. Searching backwards should move first left, then up and to the rightmost hit.