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
module	Manage DMOD modules (load, unload, enable, disable, info, list)

Module Command

The module command provides module management functionality:

• module load <name> - Load a module by name
• module unload <name> - Unload a loaded module
• module enable <name> - Enable a module
• module disable <name> - Disable a module
• module info <name> - Display detailed information about a module (name, version, author, path, architecture, required modules)
• module list - List all available modules with their names, versions, and paths

Example usage:

# List all available modules
module list

# Get information about a specific module
module info dmell

# Load a module
module load my_module

# Enable a module
module enable my_module

# Disable a module
module disable my_module

# Unload a module
module unload my_module

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.