A novel Unix shell

This project aims to explore the potentials of the Unix shell. It is a work in progress; things will change without warning.

The wiki has a random list of things you might want to know. The issues list contains many things I'm working on.

The Interface

Syntax highlighting (also showcasing right-hand-side prompt):

Tab completion for files:

Navigation mode (triggered with ^N, inspired by ranger):

Planned features:

Auto-suggestion (like fish)
Programmable line editor
Directory jumping (#27)
A vi keybinding that makes sense
History listing (like ptpython)
Intuitive multiline editing

The Language

Some things that the language is already capable of:

External programs and pipelines: (~> is the prompt):

~> vim README.md
...
~> cat -v /dev/random
...
~> dmesg | grep -i acpi
...

Arithmetics using the prefix notation:
```
~> + 1 2
▶ 3
~> mul (+ 1 2) 3
▶ 9
```

Quoting:

~> echo "|  Ceci n'est pas une pipe."
|  Ceci n'est pas une pipe.

Lists and maps:

~> println list: [a list] map: [&key=value]
list: [a list] map: [&key=value]
~> println [a b c][0]
a
~> println [&key=value][key]
value

Variables:
```
~> v=[&foo=bar]; put $v[foo]
▶ bar
```

Defining functions:

~> fn map [f xs]{ put [(put $@xs | each $f)] }

Lisp-like functional programming:

~> map [x]{+ 10 $x} [1 2 3]
[11 12 13]
~> map [x]{div $x 2} (map [x]{+ 10 $x} [1 2 3])
[5.5 6 6.5]

More natural concatenative style:

~> put 1 2 3 | each [x]{+ 10 $x} | each [x]{div $x 2}
▶ 5.5
▶ 6
▶ 6.5

A separate env: namespace for environmental variables:

~> put $env:HOME
▶ /home/xiaq
~> env:PATH=$env:PATH":/bin"

Getting elvish

Prebuilt binaries

Prebuilt binaries are available for 64-bit Linux and Mac OS X. They are always built using the latest commit that builds. Download the archive and use sudo tar xfJ elvish-*.tar.xz -C /usr/bin to install.

Building It Yourself

Go >= 1.5 is required. Linux is fully supported. It is likely to work on BSDs and Mac OS X. Windows is not supported yet.

The main binary can be installed using go get github.com/elves/elvish. There is also an auxiliary program called elvish-stub; install it with make stub. Elvish is funtional without the stub, but job control features depend on it.

If you are lazy and use bash for zsh now, here is something you can copy-paste into your terminal:

export GOPATH=$HOME/go
export PATH=$PATH:$GOPATH/bin
mkdir -p $GOPATH

go get github.com/elves/elvish
make -C $GOPATH/src/github.com/elves/elvish stub

for f in ~/.bashrc ~/.zshrc; do
    echo -e 'export GOPATH=$HOME/go\nexport PATH=$PATH:$GOPATH/bin' >> $f
done

How To Write Go Code explains how $GOPATH works.

Name

In roguelikes, items made by the elves have a reputation of high quality. These are usually called elven items, but I chose elvish for an obvious reason.

The adjective for elvish is also "elvish", not "elvishy" and definitely not "elvishish".