Process ID (PID) Regex for JavaScript

What this pattern does

This page provides a well-structured, multi-part regular expression for matching process id (pid), ported and verified for JavaScript. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your JavaScript project — whether you're validating in an Express middleware, a Next.js API route, or a client-side form.

Javascript Implementation

// Process ID (PID)
// ReDoS-safe | RegexVault — Dev & Systems > Shell

const processIdPidRegex = /^(?:[1-9][0-9]{0,5}|[1-3][0-9]{6}|4194304)$/;

function validateProcessIdPid(input: string): boolean {
  return processIdPidRegex.test(input);
}

// Example
console.log(validateProcessIdPid("1")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Dev & Systems > Shell category and carries a ReDoS-safe certification. That matters for JavaScript developers because especially critical in long-running Node.js event loops where a ReDoS vulnerability can block the entire process. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

PID 1 is always init/systemd. Linux defaults to max PID 32768 (/proc/sys/kernel/pid_max), configurable up to 4194304 (2^22). PID 0 is not a valid kill/signal target.