npm / npm/cli

[BUG] npm run on Windows mishandles backslash escaping

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Bug
Dominant language
JavaScript
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Avg merge
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Merged PRs (30d)
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Description

Is there an existing issue for this?
  • I have searched the existing issues
This issue exists in the latest npm version
  • I am using the latest npm
Current Behavior

package.json

{
    "scripts": {
        "test": "printf '%s' '\\\\' | od -c"
    }
}

Using npm run

$ npm run test

> test
> printf '%s' '\\' | od -c

0000000   \
0000001

Using git-bash

$ printf '%s' '\\' | od -c
0000000   \   \
0000002
Expected Behavior
$ npm run test

> test
> printf '%s' '\\' | od -c

0000000   \   \
0000002

In Linux (Ubuntu 24.04.2 LTS) this works as expected

Steps To Reproduce

See Current Behavior section

Environment
  • npm: 11.11.1
  • Node.js: v24.14.0
  • OS Name: Windows 11 Pro

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Reproduce the package.json script with npm run on Windows 11, then compare its output with direct git-bash and Ubuntu runs. Trace the npm run command path involved in Windows argument escaping; done means the backslash is preserved and od -c reports the expected two-byte output.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript, node.js
Domain
cli, tooling
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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