sced - simple Synchronous Command Execution in Deno

Table of Contents

Introduction

Sced is a lightweight streamlined package for the Deno runtime that provides a simple way to synchronously execute shell commands and retrieve the output directly as a string or to pipe to stout.

Features

  • Execute commands: Sced allows the execution of shell commands directly from your Deno application, and simply retrieve stdout or pipe to deno's stdout.

  • Simple: Using tagged template literals makes the command syntax clean, clear and easy to read.

  • Synchronous: Sced executes commands synchronously and returns the standard output directly.

  • No dependecies: sced is dependent on the Deno runtime only.

Limitations

Sced is synchronous

This means that the execution of commands will block the main thread until the command completes. This can be problematic for long-running commands or commands that require user input. For these cases, consider using Deno's asynchronous capabilities or a different package.

Vulnerable to command injection attacks

Sced executes shell commands directly, which can be a security risk if the commands are not properly sanitized. Be sure to validate and sanitize all inputs to prevent command injection attacks.

No piping

For now sced does not support piping or chaining multiple commands together. This may be added in future versions.
So the following for example will not work:

const files:string = $s`ls | grep .ts`;

ls: cannot access '|': No such file or directory
ls: cannot access 'grep': No such file or directory
ls: cannot access '.ts': No such file or directory
error: Uncaught (in promise) Error: "ls | grep .ts" command failed, with exit code 2
        throw new CommandfailureErr({ cmd: comand, args, exitCode: cmdOut.code });

Usage

sced is incredibly straightforward to use. To execute a command, simply use the $ function with a tagged template literal containing your command.

Examples

To String

import { $s } from "https://raw.githubusercontent.com/bitBeater/sced/v1.1.0/src/mod.ts";

const files:string = $s`ls`;
// files == "deno.jsonc  LICENSE  README.md  src"

To Stdout

import { $$ } from "https://raw.githubusercontent.com/bitBeater/sced/v1.1.0/src/mod.ts";

const exitCode:number = $$`ls`;
// will print to stdout:
// deno.jsonc  LICENSE  README.md  src

To Uint8Array

import { $b } from "https://raw.githubusercontent.com/bitBeater/sced/v1.1.0/src/mod.ts";

const byteArray:Uint8Array = $b`curl https://filesamples.com/samples/image/jpg/sample_640%C3%97426.jpg`;

Troubleshooting

For issues related to sced:

  • Ensure Deno has the necessary permissions to execute shell commands --allow-run.
  • Verify that commands are correctly formatted as tagged template literals.

Contributors

Contributions to the sced project are welcome. Please refer to the project's GitHub repository for guidelines on how to contribute.