npm commands: A useful npm reference for initializing Node.js projects, managing dependencies, running scripts and reviewing security advisories. This guide explains what each command does, its syntax, practical examples, useful options, and common mistakes. Commands are shown for typical installations; flags can vary across operating-system and tool versions.
Before you start
Open a terminal appropriate for the operating system shown in the examples. Check that the required tool is installed and that you are running it with the permissions needed for your task. Replace sample names, paths, hostnames and IDs with values from your own environment.
Syntax at a glance
Square brackets usually indicate optional arguments, while uppercase words such as FILE, HOST and PACKAGE are placeholders that you replace. Keep quotes around paths or text that contains spaces. Commands should be tested on a safe sample before being used in production.
Quick command reference
| Command | What it does | Example | Useful options |
|---|---|---|---|
npm --version | Check the installed npm version | npm --version | node --version checks Node.js separately |
npm init | Create a package.json manifest | npm init -y | -y accepts defaults; npm init interactively asks project questions |
npm install | Install project dependencies | npm install express | -D saves a development dependency; npm ci installs from the lockfile cleanly |
npm run | Run a script defined in package.json | npm run build | npm run lists available scripts when no script is specified |
npm audit | Report known vulnerability advisories in dependencies | npm audit | --omit=dev focuses the report on production dependencies; fix can make breaking updates |
Command syntax and examples explained
1. npm --version
Purpose: Check the installed npm version.
Syntax
npm --versionExample
npm --versionOptions and notes: node --version checks Node.js separately.
npm ships with many Node.js distributions but versions can differ.
2. npm init
Purpose: Create a package.json manifest.
Syntax
npm init [OPTIONS]Example
npm init -yOptions and notes: -y accepts defaults; npm init interactively asks project questions.
Review name, license and scripts before publishing a package.
3. npm install
Purpose: Install project dependencies.
Syntax
npm install [PACKAGE]Example
npm install expressOptions and notes: -D saves a development dependency; npm ci installs from the lockfile cleanly.
Commit package-lock.json for reproducible installs.
4. npm run
Purpose: Run a script defined in package.json.
Syntax
npm run SCRIPTExample
npm run buildOptions and notes: npm run lists available scripts when no script is specified.
Only run scripts from a project you trust; scripts can execute arbitrary code.
5. npm audit
Purpose: Report known vulnerability advisories in dependencies.
Syntax
npm audit [OPTIONS]Example
npm auditOptions and notes: --omit=dev focuses the report on production dependencies; fix can make breaking updates.
Review the proposed changes rather than applying major dependency upgrades blindly.
Common mistakes and troubleshooting
- Command not found: confirm the tool is installed and available on your PATH; open a new terminal after changing PATH.
- Permission denied: verify the current account, file permissions and target path. Use administrator/root privileges only when genuinely required.
- Unexpected output: check the command version, quoting, current directory and exact arguments. Consult the local help or manual for options supported by your build.
- Destructive operations: preview the target and keep a backup before deleting data, rewriting history, flashing a partition or changing system configuration.
Safety tips
Review every command before running it, especially commands that delete files, change permissions, flash firmware, alter a database or expose a network service. For network scanning and remote administration, work only on devices and systems you own or are authorized to test. Keep credentials, private keys, access tokens and log files private.
Frequently asked questions
Do these commands work on every system?
Not always. Some commands are specific to Windows, Linux, Android, a particular package manager or an installed tool version. Use the syntax shown for your platform and check local help when a flag is unavailable.
Can I copy and run every example exactly?
Use the examples as templates. Replace placeholders such as filenames, package IDs, hostnames and paths with your own values, and verify the effect before executing a command that changes data or system state.
Conclusion
Use this reference as a starting point, then confirm flags in the tool’s official help or manual for your installed version. A clear understanding of syntax, options and side effects makes command-line work more reliable.