sage-guess-package-system

#!/bin/sh
#
# First test for user-installable package systems, then system package systems
if conda --version > /dev/null 2>&1; then
    if [ -z "$CONDA_DEFAULT_ENV" ]; then
        printf >&2 "(ignoring conda because no environment is active) "
    else
        echo conda
        exit
    fi
fi
if brew --version > /dev/null 2>&1; then
    echo homebrew
elif port version > /dev/null 2>&1; then
    echo macports
elif emerge --version > /dev/null 2>&1; then
    echo gentoo
elif apt-get --version > /dev/null 2>&1; then
    echo debian
elif dnf5 --version > /dev/null 2>&1; then
    echo fedora
elif pacman --version > /dev/null 2>&1; then
    echo arch
elif slackpkg --version > /dev/null 2>&1; then
    echo slackware
elif zypper --version > /dev/null 2>&1; then
    echo opensuse
elif apk --version > /dev/null 2>&1; then
    echo alpine
elif xbps-install --version > /dev/null 2>&1; then
    echo void
elif pkg -v > /dev/null 2>&1; then
    echo freebsd
else
    echo unknown
fi