dmell

DMOD Shell - A lightweight shell implementation for the DMOD module system.

Overview

dmell is a shell interpreter designed for the DMOD (Dynamic Module) system. It provides a command-line interface for executing commands, running scripts, and managing variables.

Features

• Built-in Commands: Basic shell commands like echo, cd, pwd, set, unset, export, and exit
• External Command Modules: Complex commands (cp, mv, ls, cat, mkdir, touch, head, tail, grep, rm, rmdir, find, which, printf) available as separate DMOD modules
• Script Execution: Support for .dme script files
• Variable Management: Environment variables and shell variables support
• Shebang Support: Execute scripts with custom interpreters

Built-in Commands

Command	Description
echo	Print arguments to standard output
cd	Change current directory
pwd	Print current working directory
set	Set a shell variable
export	Export a variable
unset	Unset a variable
exit	Exit the shell with optional exit code

Command Modules

Complex file system commands are implemented as separate DMOD modules for better modularity.

These modules can be installed separately using the dmf-get package manager tool:

dmf-get cp
dmf-get mv
dmf-get ls
dmf-get cat
dmf-get mkdir
dmf-get touch
dmf-get head
dmf-get tail
dmf-get grep
dmf-get rm
dmf-get rmdir
dmf-get find
dmf-get which
dmf-get printf

Module	Description	Documentation
cp	Copy files	commands/cp/README.md
mv	Move/rename files	commands/mv/README.md
ls	List directory contents	commands/ls/README.md
cat	Display file contents	commands/cat/README.md
mkdir	Create directories	commands/mkdir/README.md
touch	Create empty files / update mtime	commands/touch/README.md
head	Display first lines of file	commands/head/README.md
tail	Display last lines of file	commands/tail/README.md
grep	Search text in files	commands/grep/README.md
rm	Remove files	commands/rm/README.md
rmdir	Remove empty directories	commands/rmdir/README.md
find	Search for files	commands/find/README.md
which	Locate module path	commands/which/README.md
printf	Format and print text	commands/printf/README.md

Building

Prerequisites

• CMake 3.18 or higher
• A C compiler (GCC, Clang, etc.)
• DMOD SDK

Build Instructions

mkdir -p build
cd build
cmake ..
cmake --build .

Usage

Running the Shell on PC

On PC, dmell modules are executed using the dmod_loader tool from the DMOD repository:

dmod_loader dmell.dmf

For more details about the loader, see the dmod repository.

Running a Script

dmod_loader dmell.dmf script.dme

Script Example

#!/bin/dmell

echo "Hello, dmell!"
set myvar=value
echo "myvar = $myvar"

Project Structure

dmell/
├── src/                  # Main shell source files
├── include/              # Header files
├── commands/             # Command modules
│   ├── cp/              # Copy command module
│   ├── mv/              # Move command module
│   ├── ls/              # List command module
│   ├── cat/             # Cat command module
│   ├── mkdir/           # Create directory module
│   ├── touch/           # Create empty file module
│   ├── head/            # Display first lines module
│   ├── tail/            # Display last lines module
│   ├── grep/            # Search text module
│   ├── rm/              # Remove files module
│   ├── rmdir/           # Remove directories module
│   ├── find/            # Search for files module
│   ├── which/           # Locate module module
│   └── printf/          # Format and print module
├── examples/            # Example scripts
└── CMakeLists.txt       # Build configuration

License

See LICENSE for details.