• #Python, #Bash, #UV, #Pip, #Fedora, #Pew

I finally made the switch from pip to uv recently. uv is much quicker that pip. I won't go into how/why here, but I will link you to this video that explains it. When working with packages such as PyNeuroML that have quite a few dependencies, the speed up begins to matter, especially when one is developing and may create and remove virtual environments quite often.

I used to use Pew to manage my Python virtual environments. It is a great tool. Unfortunately, it isn't quite maintained any more, and that means support for things like uv are probably not going to happen soon.

I went looking for a similar wrapper around uv and there are some, but they're simple enough where I thought writing my own bash functions/aliases is probably preferable. So, here's what I've added to my bashrc. They are a number of functions/aliases to:

• list virtual environments
• create a new virtual environment using uv
• activate virtual environments
• remove virtual environments
• install packages using uv

A simple bash shell completion function is also setup. The listing and removal functions aren't really uv specific here, but I prefix them with uv for consistency.

(I don't use another shell, so please adapt these to whatever you use):

# uv helpers
export VIRTUAL_ENV_HOME="$HOME/.virtualenvs/"
uvnew () {
    if command -v uv 2>&1 > /dev/null
    then
        pushd $VIRTUAL_ENV_HOME && uv venv "$@" && popd
    else
        echo "uv not installed"
    fi
}
uvls () {
    ls $VIRTUAL_ENV_HOME
}
uvrm () {
    venv_name=$1
    read -p "Delete env \"$venv_name\"? Are you sure? (Yy)" -n 1 -r
    # (optional) move to a new line
    echo
    # input is stored in REPLY if no var is given to read
    if [[ $REPLY =~ ^[Yy]$ ]]
    then
        echo "Removing $VIRTUAL_ENV_HOME/$venv_name"
        rm -rf $VIRTUAL_ENV_HOME/$venv_name
    fi
}
_venv_completions () {
    local cur
    cur="${COMP_WORDS[COMP_CWORD]}"
    pushd $VIRTUAL_ENV_HOME 2>&1 >/dev/null
        COMPREPLY=($(compgen -o dirnames -- "$cur"))
    popd >/dev/null 2>&1
}
uvactivate () {
    venv_name=$1
    if [ -e "$VIRTUAL_ENV_HOME/$venv_name/bin/activate" ]
    then
        source "$VIRTUAL_ENV_HOME/$venv_name/bin/activate"
    else
        echo "Could not find activation script"
        echo "Available venvs are"
        uvls
    fi
}
complete -F _venv_completions uvactivate
complete -F _venv_completions uvrm

alias uvpip="uv pip"

On Fedora, uv is in the repositories, so it can be installed with:

sudo dnf install uv

If you have your own wrappers for working with uv that are better than these simple bits, please drop me a word.