Bash shell script to set Firefox homepage

firefox_set_homepage.sh

#!/bin/bash
# Script to change Firefox homepage in Linux
#

# Full path to 'profiles.ini'
PROFILES_INI=/home/$(whoami)/.mozilla/firefox/profiles.ini

if [ ! $1 ]; then
    echo "Set URL as 1st argument"
    exit 1
fi

if [ ! -f "$PROFILES_INI" ]; then
    echo "Could not find profiles.ini:" $PROFILES_INI
    exit 1
fi

# Assumes one Firefox profile
prefs_file=$(echo "${PROFILES_INI}" | sed 's/profiles.ini$//g')$(grep "Path=" "$PROFILES_INI" | sed 's/Path=//g')"/prefs.js"

if [ ! -f "$prefs_file" ]; then
    echo "Could not find preferences file:" $prefs_file
    exit 1
fi

echo "Editing prefs.js file:" $prefs_file

# Look for: user_pref("browser.startup.homepage", ".*");
sed -i "s/\(^user_pref(\"browser.startup.homepage\", \"\).*\(\");\)/\1${1}\2/g" "$prefs_file"

echo "Firefox homepage has been changed to:" $1
exit 0