How to fix pip freeze returns an error:: Permission denied: hg?

Updated: 28 September 2026 · Applies to: Ubuntu 24.04, Debian 12, AlmaLinux 9 and Rocky Linux 9 (pip 25)

pip freeze lists installed Python packages. For packages installed in editable mode from a Mercurial repository (pip install -e hg+…), pip runs the hg command to find the repository address. Permission denied: 'hg' means that command is missing or cannot be run.

Fixes

• Install Mercurial: dnf install mercurial (AlmaLinux/Rocky, EPEL) or apt install mercurial (Ubuntu/Debian), or pip install mercurial inside your virtual environment.
• Leave editable packages out: pip freeze --exclude-editable.
• List plain name==version lines without looking at repositories: pip list --format=freeze.
• If hg exists but is not executable, check the file: ls -l $(which hg).

Avoid it in the future

• Work inside a virtual environment per project (python3 -m venv venv), so pip never touches system packages.
• For deployments, install from released packages or Git tags instead of editable checkouts, and record versions in requirements.txt.

Check your pip

python3 -m pip --version        # which pip and which Python it belongs to
python3 -m pip install --upgrade pip     # inside a virtual environment

Running pip as python3 -m pip makes sure you use the pip of the Python you expect.