Linux SDL game controller database fixer and updater

#!/usr/bin/env bash

# Script written by Swiftpaw - 2018/09/02

# Define color functions
echo_red() {
echo -e "\e[1m\e[91m$1\e[0m"
}
echo_green() {
echo -e "\e[92m$1\e[0m"
}
echo_greenbold() {
echo -e "\e[1m\e[92m$1\e[0m"
}
echo_yellow() {
echo -e "\e[93m$1\e[0m"
}

# Define variables
NEWFILEOK=0
OLDFILEOK=0

# Verify script is running as normal user
if ! ((EUID)); then
        echo_red "Do not run script with root privilages.  Script needs to modify a user's profile files.  Changes to /etc/environment file are not possible for the multiple controller support which this script enables."
        exit 1
fi

# Change to user's home directory
echo_green "Changing directory to $HOME"
cd $HOME

# Download newest database file
echo_green "Downloading newest controller database file"
wget -nv https://raw.githubusercontent.com/gabomdq/SDL_GameControllerDB/master/gamecontrollerdb.txt -O ./gamecontrollerdb.txt-new

# Check if download was successful or not
# Check if downloaded file exists.
if [ -e ./gamecontrollerdb.txt-new ] ; then
    # Check if downloaded file is greater than 180 lines.  If so, set NEWFILEOK=1, else set to 0.
    if [ $(cat ./gamecontrollerdb.txt-new | wc -l) -ge 180 ] ; then
        echo_green "New database download appears to be OK"
        NEWFILEOK=1
    else
        echo_yellow "New database download file is under 180 lines, so not using it"
        NEWFILEOK=0
    fi
else
# If downloaded file doesn't exist,  don't use it by setting NEWFILEOK=0.
    echo_yellow "New database download file not found, so download must have failed."
    NEWFILEOK=0
fi

# Check if old database file exists...
if [ -e ./gamecontrollerdb.txt ] ; then
    # ...and if it has enough lines.
    if [ $(cat ./gamecontrollerdb.txt | wc -l) -gt 180 ] ; then
        OLDFILEOK=1
        echo_green "Old database file exists and looks okay"
    else
        OLDFILEOK=0
        echo_yellow "Old database file exists, but doesn't look okay, has less than 180 lines"
    fi
else
    OLDFILEOK=0
    echo_green "No existing database file found"
fi

# If old database file doesn't exist or is bad, and new database download failed, exit.
if [ $OLDFILEOK -eq 0 ] && [ $NEWFILEOK -eq 0 ] ; then
    echo_red "Download failure, and no $HOME/gamecontrollerdb.txt file found or file has less than 180 lines in it.  Assuming this is a new database installation.  Please find a working source for the game database file which was located at https://raw.githubusercontent.com/gabomdq/SDL_GameControllerDB/master/gamecontrollerdb.txt and https://github.com/gabomdq/SDL_GameControllerDB/blob/master/gamecontrollerdb.txt"
    exit 1
fi

# If both old and new files exist and are OK, make a backup of old file, then move the new one into its place.
if [ $OLDFILEOK -eq 1 ] && [ $NEWFILEOK -eq 1 ] ; then
    mv ./gamecontrollerdb.txt ./gamecontrollerdb.txt-backup
    echo_green "Backup of gamecontrollerdb.txt saved to $HOME/gamecontrollerdb.txt-backup"
    mv ./gamecontrollerdb.txt-new ./gamecontrollerdb.txt
    echo_green "Newly downloaded game controller database file saved to $HOME/gamecontrollerdb.txt"
    # Compare the old and new files and report if there is a difference
    if [ $(diff ./gamecontrollerdb.txt ./gamecontrollerdb.txt-backup | wc -l) -eq 0 ] ; then
        echo_yellow "New database file doesn't contain any updates"
    else
        echo_greenbold "New database file contained an update!"
    fi
fi

# If downloaded new database file is the only file (for new installs), just move it into place
if [ $OLDFILEOK -eq 0 ] && [ $NEWFILEOK -eq 1 ] ; then
        mv ./gamecontrollerdb.txt-new ./gamecontrollerdb.txt
        echo_green "Newly downloaded game controller database file saved to $HOME/gamecontrollerdb.txt"
fi

# Only take the Linux controller lines from the database file, and save them to .controller_config
grep Linux gamecontrollerdb.txt | grep -v '# Linux' > .controller_config

# Add SDL_GAMECONTROLLERCONFIG variable text to .controller_config file and wrap the variable in quotation marks
sed -i '1s/^/export SDL_GAMECONTROLLERCONFIG="/' .controller_config
sed -i '$s/$/&"/' .controller_config

echo_green "Database variable source file created from $HOME/gamecontrollerdb.txt and placed into $HOME/.controller_config"

# Configure the user's profile to source the SDL_GAMECONTROLLERCONFIG variable from the .controller_config file
if [ -e .bashrc ] ; then
    if ! $(grep -q '. "$HOME/.controller_config"' .bashrc); then
        echo '. "$HOME/.controller_config"' >> .bashrc
        echo_green "Line to source .controller_config was added to your .bashrc file"
    fi
fi

if [ -e .bash_profile ] ; then
        if ! $(grep -q '. "$HOME/.controller_config"' .bash_profile); then
                echo '. "$HOME/.controller_config"' >> .bash_profile
        echo_green "Line to source .controller_config was added to your .bash_profile file"
        fi
fi

if [ -e .profile ] ; then
        if ! $(grep -q '. "$HOME/.controller_config"' .profile); then
                echo '. "$HOME/.controller_config"' >> .profile
        echo_green "Line to source .controller_config was added to your .profile file"
        fi
fi

# Print that script has finished, wait in case user used temporary terminal
echo_greenbold "Script complete.  Please log out and back in."
echo_greenbold "Waiting 30 seconds, or hit CTRL-C to exit."
sleep 30