Modified INSTALL.md

- Point out the difference between passing path/incpath as arguments
   and as variables

INSTALL.md

@@ -9,6 +9,10 @@ For Pizza to work, you need a running mail service (either server, smarthost or
 ### The simple way
 
 Install Pizza by running "install.sh" from the base-directory.
+install.sh takes two arguments: a prefix (the path where to place the executable parts; defaults to "/usr/local/") and
+an incprefix (the path where to place the message contents/ASCII-images; defaults to "<prefix>/share").
+To set incprefix, passing prefix beforehands is mandatory!
+You may also pass the environement variables "$PATH" and "$INCPATH", even though given arguments take precedence.
 
 ### The hard way
 
@@ -20,4 +24,4 @@ mkdir -p $SHAREDIR/pizza
 install -m 644 assets/* $SHAREDIR/pizza/
 ```
 
-Afterwards, you have to set the variable `$PIZZAINC` to `$SHAREDIR` accordingly.
+Afterwards, you have to set the variable `$PIZZAINC` to `$SHAREDIR` accordingly.

install.sh

@@ -6,29 +6,35 @@
 
 
 if [ "$1" ]; then
-	PREFIX:="$1"
+	PREFIX="$1"
 else
 	: ${PREFIX:="/usr/local"}
 fi
 
+if [ "$2" ]; then
+	INCPREFIX="$2"
+else
+	: ${INCPREFIX:="${PREFIX}/share"}
+fi
+
 # Create necessary directories
 
-for i in "${PREFIX}/bin" "${PREFIX}/share/pizza"; do
+for i in "${PREFIX}/bin" "${INCPREFIX}/share/pizza"; do
 	if [ ! -d "$i" ]; then
 		mkdir -p "$i"
 	fi
 done
 
 install -m 755 src/pizza "${PREFIX}/bin/pizza"
-install -m 644 assets/* "${PREFIX}/share/pizza/"
+install -m 644 assets/* "${INCPREFIX}/share/pizza/"
 
 # Tell the user what to do next, if he used another PREFIX
 
-if [ "${PREFIX}" != "/usr/local" ]; then
+if [ "${INCPREFIX}" != "/usr/local" ]; then
 	echo 'Your installation path differs from /usr/local'
 	echo 'For pizza to run properly, please either modify the script'
 	echo 'or set the PIZZAINC-variable accordingly.'
 	echo '(Add the following to your ${shell}rc:'
-	echo -e "\t export PIZZAINC=\"${PREFIX}/share/pizza/\""
+	echo -e "\t export PIZZAINC=\"${INCPREFIX}/pizza/\""
 	echo ")"
 fi