Check if curl is installed and halt if not

Yeah, actually stopping would be smart.

NoFoxGiven.sh

@@ -1,11 +1,12 @@
 #!/bin/bash
 echo "NoFoxGiven Snap removal and replacement script for Firefox."
-echo "WARNING: If you have not backed up your Firefox profile, *EVERYTHING WILL BE LOST*. Close this command prompt and check the Github page for instructions on how to do so. Otherwise, press Enter to continue."
+echo "WARNING: If you have not backed up your Firefox profile, **EVERYTHING WILL BE LOST**. Close this command prompt and check the Github page for instructions on how to do so. Otherwise, press Enter to continue."
 read
 if ! command -v curl &> /dev/null
 then
-    echo "curl is not installed on your system. Install it first with sudo apt install curl, then restart this script"
+    echo "curl is not installed on your system. Install it first with sudo apt install curl, then restart this script."
     read
+    exit
 fi
 echo "Now downloading latest Standalone Firefox build"
 curl -L -o firefox.tar.bz2 "https://download.mozilla.org/?product=firefox-latest-ssl&os=linux64&lang=en-GB"
@@ -19,6 +20,7 @@ sudo rsync -a ./icons /usr/share
 sudo mv ./Firefox.desktop /usr/share/applications/
 sudo rm -r ./icons
 chmod +x /usr/share/applications/Firefox.desktop
+echo
 echo "Installation complete!"
 echo "Proceeding to remove Snap..."
 sleep 5
@@ -36,6 +38,8 @@ sudo rm -rf /var/snap
 sudo rm -rf /var/cache/snapd/
 sudo rm -rf /var/lib/snapd
 sudo apt-mark hold snapd
+echo
 echo "Removal complete! Snap has also been marked to be held back."
 echo "Script complete. You can now close this terminal."
 read
+exit