Tweak installation script

- Add TODO
- Add version
- Comment scary `rm -rf` usage

This is the first beta version, it's already useful.

virtualatex

 #!/bin/bash
 set -e
 
+VIRTUALTEX_VERSION=0.1
+
 # TODO: This is the latest version
 #       See "https://texlive.info/tlnet-archive/" for archived versions
 TexLive_Repo=${CTAN_REPO:-http://mirror.ctan.org/systems/texlive/tlnet}
@@ -12,6 +14,7 @@ setup_tinytex() { # Install Location
 	tmp="$(mktemp -d)"  # Temporary Location
 	pushd "$tmp"
 	# TexLive
+	# TODO: Cache the TexLive_URL download in `~/.cache/???`
 	wget -nc "$TexLive_URL"{,.sha512,.sha512.asc}
 	sha512sum -c "$TexLive_File.sha512"  # Verify hash
 	gpg --verify "$TexLive_File.sha512.asc" || true  # TODO: Verify GPG
@@ -32,12 +35,13 @@ setup_tinytex() { # Install Location
 	echo "- TexLive: $il_texlive"
 	echo "=> Platform (Script): $platform"
 
+	# TODO: Gate this to a `-f` flag
 	# Do it!
-	if [ -d "$il_texlive" ]; then
-		# TODO: I *think* TeXlive supports overwiting...
-		echo "=> Re-Installing TexLive"
-		rm -rf "$il_texlive"
-	fi
+	# if [ -d "$il_texlive" ]; then
+	# 	# TODO: I *think* TeXlive supports overwiting...
+	# 	echo "=> Re-Installing TexLive"
+	# 	rm -rf "$il_texlive"
+	# fi
 	echo "=> Installing TexLive @ '$il_texlive'"
 	# Ripped off from TinyTex: https://github.com/yihui/tinytex/blob/master/tools/tinytex.profile
 	cat >"$tmp/tinytex.profile" <<-TINYTEX
@@ -76,6 +80,8 @@ setup_tinytex() { # Install Location
 	# "$tlmgr" --repository "https://texlive.info/tlgpg/" install tlgpg
 	echo "=> Add symlinks to '$il_bin'"
 	"$tlmgr" path add
+	echo "=> Mark virtualtex installation"
+	echo "VERSION=$VIRTUALTEX_VERSION" >"$il_texlive/virtualtex"
 
 	# Remove detritus
 	popd
@@ -83,5 +89,15 @@ setup_tinytex() { # Install Location
 }
 
 install_location="${1:-"$PWD"}"
-test -d "$install_location"
-setup_tinytex "$install_location"
+if [ -e "$install_location" ]; then
+	if test -d "$install_location"; then
+		echo "Existing Location: $install_location" >&2
+		exit 1
+	else
+		echo "Invalid Location: $install_location" >&2
+		exit 2
+	fi
+else
+	mkdir "$install_location"
+	setup_tinytex "$install_location"
+fi