script for installing nix software in a soft sandbox

nix-sandbox.sh

#!/bin/sh
which /bin/sh &>/dev/null || echo /bin/sh not found!! Try putting /bin/bash at begin of script!
which /bin/sh &>/dev/null || exit

read -e -p "Nix package name: " -i "firefox" nixPackageName || exit
read -e -p "Sandbox home folder: " -i "$HOME/.home/$nixPackageName" sandboxHome || exit
read -e -p "App calling command: " -i "$nixPackageName" appCmd || exit
echo downloading package...
nix-shell -p $nixPackageName --command exit
echo preparing sandbox home...
mkdir -p $sandboxHome || exit



#####################################################################################################
# run.sh                                                                                            #
#####################################################################################################
printf "#!/bin/sh                                                                                   #
                                                                                                    #
export package=$nixPackageName                                                                      #
export homefolder=$sandboxHome                                                                      #
export cmd=\"$appCmd $@\"                                                                           #
                                                                                                    #
                                                                                                    #
export HOME=\$homefolder                                                                            #
mkdir -p ~/.config/nixpkgs/                                                                         #
printf \"{ allowUnfree = true; }\" > ~/.config/nixpkgs/config.nix                                   #
nix-shell -p \$package --command \"\$cmd\"" > $sandboxHome/run.sh && chmod +x $sandboxHome/run.sh   #
#####################################################################################################


echo
echo "continuing will create a launcher link. Cancel with Ctrl+C"
read -e -p "Launcher Link: " -i "$HOME/.local/share/applications/$nixPackageName.desktop" launcherFile || exit
read -e -p "Launcher Name: " -i "$(echo $nixPackageName | sed 's/./\u&/')" launcherName || exit
cp $(find /nix/store/*$nixPackageName* -name "*png" | head -n 1) $sandboxHome/icon.png

#####################################
# launch.desktop                    #
#####################################
printf "[Desktop Entry]             #
Type=Application                    #
Encoding=UTF-8                      #
Name=$launcherName                  #
Icon=$sandboxHome/icon.png          #
Exec=$sandboxHome/run.sh            #
Terminal=false;" > $launcherFile    #
#####################################