add installation instructions

README.md

@@ -22,6 +22,19 @@ Notes:
 	Water may also be used in place of beer
 	Try adding your choice of spices and/or herbs into the dough for more flavor
 ```
+
+### Installation
+As mentioned at the beginning of this file, `bc` is a requirement to running, along with a few other common shell utilities.
+While it is possible to simply clone this git repositiory and simply run `./pizza.sh`, one might be interested in a system wide installation. 
+In that case, the recommended install instructions are as follows:
+```
+sudo su
+cd /usr/local/share/
+git clone https://git.skeh.site/ida/pizzacalc.git
+ln -s /usr/local/share/pizzacalc/pizza.sh /usr/local/bin/pizza
+```
+(Most GNU/Linux distributions will already have /usr/local/bin/ in their paths.)
+
 ### Recipe (specifically for -r quick)
 ```
 How to make the quick calculator pizza, standmixer edition:

pizza.sh

@@ -137,13 +137,14 @@ case $1 in # this parses the first argument (and actually calls our main functio
 				DFSI="$FSI"
 			fi
 			read -p "Flour per square inch [$DFSI]: " FSI
-			case $DIME in
+			case "$DIME" in
 				+([0-9])?(.)*([0-9])x+([0-9])?(.)*([0-9]))
-					WIDTH=$(echo $DIME | cut -d "x" -f 1)
+					WIDTH=$(echo "$DIME" | cut -d "x" -f 1)
-					LENGTH=$(echo $DIME | cut -d "x" -f 2)
+					LENGTH=$(echo "$DIME" | cut -d "x" -f 2)
 					SQUAREPAN=y
 					panarea;;
 				+([0-9])?(.)*([0-9]))
+					WIDTH="$DIME"
 					SQUAREPAN=n
 					panarea;;
 			esac