Interactive Shell

What’s different about Murex’s interactive shell?

Table of Contents

Overview

Aside from Murex being carefully designed with scripting in mind, the interactive shell itself is also built around productivity. To achieve this we wrote our own readline library. Below is an example of that library in use:

asciicast

The above demo includes the following features of Murex’s bespoke readline library:

readline

Murex uses a custom readline library to enable support for new features in addition to the existing uses you’d normally expect from a shell. It is because of this, Murex provides one of the best user experiences of any of the shells available today.

Hotkeys

A full breakdown of supported hotkeys is available in the terminal-keys guide.

Autocompletion

Autocompletion happen when you press [tab] and will differ slightly depending on what is defined in autocomplete and whether you use the traditional POSIX pipe token, |, or the arrow pipe, ->.

The | token will behave much like any other shell however -> will offer suggestions with matching data types (as seen in runtime --methods). This is a way of helping highlight commands that naturally follow after another in a pipeline. Which is particularly important in Murex as it introduces data types and dozens of new builtins specifically for working with data structures in an intelligent and readable yet succinct way.

You can add your own commands and functions to Murex as methods by defining them with method. For example if we were to add jq as a method:

method define jq {
    "Stdin":  "json",
    "Stdout": "@Any"
}

Syntax Completion

Like with most IDEs, Murex will auto close brackets et al.

asciicast

Syntax Highlighting

Pipelines in the interactive terminal are syntax highlighted. This is similar to what one expects from an IDE.

Syntax highlighting can be disabled by running:

config set shell syntax-highlighting off

Spellchecker

Murex supports inline spellchecking, where errors are underlined. For example

asciicast

This might require some manual steps to enable, please see the spellcheck user guide for more details.

Hint Text

The hint text is a (typically) blue status line that appears directly below your prompt. The idea behind the hint text is to provide clues to you as type instructions into the prompt; but without adding distractions. It is there to be used if you want it while keeping out of the way when you don’t want it.

Configuring Hint Text Colour

By default the hint text will appear blue. This is also customizable:

» config get shell hint-text-formatting
{BLUE}

The formatting config takes a string and supports ANSI constants.

It is also worth noting that if colour is disabled then the hint text will not be coloured even if hint-text-formatting includes colour codes:

» config set shell color false

(please note that syntax highlighting is unaffected by the above config)

Custom Hint Text Statuses

There is a lot of behavior hardcoded into Murex like displaying the full path to executables and the values of variables. However if there is no status to be displayed then Murex can fallback to a default hint text status. This default is a user defined function. At time of writing this document the author has the following function defined:

config set shell hint-text-func {
    trypipe <!null> {
        git status --porcelain -b -> set gitstatus
        $gitstatus -> head -n1 -> regexp 's/^## //' -> regexp 's/\.\.\./ => /'
    }
    catch {
        out "Not a git repository."
    }
}

…which produces a colorized status that looks something like the following:

develop => origin/develop

Disabling Hint Text

It is enabled by default but can be disabled if you prefer a more minimal prompt:

» config set shell hint-text-enabled false

Preview

Murex supports a couple of full screen preview modes:

Autocomplete Preview

Enabled via [f1]

This displays a more detailed view of each parameter you’re about to pass to a command, without you having to run that command nor leave the half-completed command line.

It can display: * man pages * custom guides like https://cheat.sh * information about binary files * contents of text files * and even images too!

Command Line Preview

Enabled via [f9]

The Command Line Preview allows you to view the output of a command line while you’re still writing it. This interactivity removes the trial-and-error from working with complicated command line incantations. For example parsing parsing complex documents like machine generated JSON becomes very easy.

This does come with some risks because most command line operations change you systems state. However Murex comes with some guardrails here too:

Safer Pasting

A common behaviour for command line users is to copy and paste data into the terminal emulator. Some shells like Zsh support Bracketed paste but that does a pretty poor job of protecting you against the human error of pasting potentially dangerous contents from an invisible clipboard.

Where Murex differs is that any multi-line text pasted will instantly display a warning prompt with one of the options being to view the contents that you’re about to execute.

This gives you piece-of-mind that you are executing the right clipboard content rather than something else you copied hours ago and forgotten about.

Smarter Error Messages

Errors messages in most shells suck. That’s why Murex has taken extra care to give you as much useful detail as it can.

See Also


This document was generated from gen/user-guide/interactive-shell_doc.yaml.

This site's content is rebuilt automatically from murex's source code after each merge to the master branch. Downloadable murex binaries are also built with the website.

Last built on Wed May 29 22:34:12 UTC 2024 against commit 59427ac59427acc045d10935b148c16c2c3860e1470e756.

Current version is 6.0.1000 which has been verified against tests cases.