Aeth

A hybrid Linux shell written in Haskell that bridges traditional text-based shells with modern structured data.

• Version: 0.4.0
• License: MIT

Aeth is a polymorphic shell that supports both traditional Unix commands and structured data operations:

• Raw Mode: ls returns text (traditional shell behavior)
• Structured Mode: @ls returns structured data (tables with columns)

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Features

Core Shell

• Fast startup (~25ms)
• Process management via fork/exec
• Path resolution through $PATH
• Native I/O redirection (>, >>, <, 2>, 2>>, &>)
• Piping and command chaining (|, &&, ||, ;)
• Environment variable expansion
• Brace expansion ({a,b,c}, {1..10}, {a..z})
• Extended globbing (*/.txt recursive patterns)
• Tab completion for commands and paths
• Command history with up/down arrow navigation
• Signal handling (Ctrl+C, Ctrl+D)
• Proper quoting support
• Custom source files and binary paths

Built-in Commands

Command	Description
cd [path]	Change directory (supports cd -)
pwd	Print working directory
exit	Exit shell
export KEY=VALUE	Set environment variable
unset KEY	Remove environment variable
history	Show command history
clear	Clear screen
source FILE	Execute commands from file
type CMD	Show command type
which CMD	Find executable path
echo [args]	Print arguments
true / false	Return exit codes
jobs	List background jobs
audit-verify	Verify audit log integrity
audit-export	Export audit log as JSON
audit-hash	Hash a command string

Structured Commands

Command	Description
@ls [path]	List directory as table
@ls -a	Include hidden files
@pwd	Print working directory
@ps	Process list as table
@df	Disk usage as table
@env	Environment variables
@find [path] [pattern]	Find files recursively

Structured Transformations

Command	Description
filter { .field op value }	Filter table rows
sort .field	Sort table by column
select .field1 .field2	Select specific columns
count	Count rows
unique [.field]	Deduplicate rows
head N / tail N	Take/skip N rows
json	Output as clean JSON

Filter operators: ==, !=, >, >=, <, <=, contains

Numeric fields (%CPU, %MEM, size) use numeric comparison automatically:

@ls | filter { .size > 1MB }
@ls | filter { .kind == dir }
@ps | filter { .%CPU > 1 }
@ls | filter { .permissions == rw-r--r-- }
@ls | filter { .name contains "dist" }
@find | filter { .path contains "dist" }

# Pipeline examples
@ls | filter { .kind == dir } | count
@ps | sort .%MEM | head 5
@ls | filter { .kind == file } | json

Audit Log (Blockchain-Inspired)

Every command is logged with a hash chain for tamper detection:

audit-verify     # Verify audit log integrity
audit-export     # Export audit log as JSON
audit-hash cmd   # Hash a command string

The audit log is persisted to ~/.config/aeth/audit.log with chained hashes.

Configurable Prompt

Prompt styles: minimal, powerline, simple, or custom format.

Custom prompt placeholders: {cwd}, {user}, {host}, {branch}, {exit}, {git}

Command Aliases

Define in config.toml:

alias.ll = "ls -la"
alias.la = "@ls -a"

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Installation

Requirements: GHC 9.6+ and Cabal

git clone https://github.com/prabinpanta0/aeth
cd Aeth
cabal build
cabal run aeth

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Usage

Interactive Mode

./aeth

Non-Interactive Mode

./aeth -c "ls -la"
./aeth -c "@ls"

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Configuration

Location: ~/.config/aeth/config.toml

mkdir -p ~/.config/aeth
cp config/config.toml ~/.config/aeth/config.toml

See docs/CONFIGURATION.md for details.

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Documentation

• Configuration Guide
• Architecture Overview

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Roadmap

Completed

• Fast startup (~25ms)
• Tab completion
• Proper quoting support
• Environment variable expansion
• Signal handling
• Configurable prompts
• Command history with arrow navigation
• Visual file/directory distinction
• Structured commands (@ls, @ps, @df, @env, @find)
• Structured transformations (filter, sort, select, count, unique, head, tail, json)
• Command aliases
• Full I/O redirection (via /bin/sh delegation)
• Job control (fg, bg)
• Syntax highlighting
• Auto-suggestions (fish-like history suggestions, Right arrow to accept)
• Command chaining (&&, ||, ;)
• Native I/O redirection (>, >>, <, 2>, 2>>, &>)
• Brace expansion ({a,b,c}, {1..10}, {a..z})
• Extended globbing (**/*.txt recursive patterns)
• Source files/folders feature (source.N and path.N in config)
• Numeric comparison for filter (> < >= <= auto-detect numbers)
• JSON output for LLM consumption (@ls | json)
• Blockchain-inspired audit log with hash chaining
• --help and --version flags

Planned

• Process substitution (<(cmd), >(cmd))
• Arithmetic expansion
• More structured commands

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License

MIT License - see LICENSE file.