weird issue with the version of expr and the match command vs colon

Author: dsjoerg

README.md

@@ -8,8 +8,9 @@
 
 ## Creating unit icons
 
- 1. Extract btn-unit* (and all files from special cases below) from base.MPQ and throw them in units/dds/
- 2. `cd units && bash gen.sh <size>`
+ 1. Extract btn-unit* (and all files from special cases below) from the appropriate MPQ file and throw them in units/dds/
+    The MPQ file will be Starcraft II/Mods/Liberty.SC2Mod/Base.SC2Assets for WoL units.
+ 2. `cd units && bash gen.sh <size>` for <size> in 32, 48, 76
  3. profit.
 
 ### Special cases:

units/gen.sh

@@ -14,7 +14,7 @@ for k in dds/*dds; do
 	filename=$(basename "$k")
 	extension="${filename##*.}"
 	filename="${filename%.*}"
-	m=`expr match "$filename" '\(btn-[a-zA-Z]*-[a-zA-Z]*-\)'`
+	m=`expr "$filename" : '\(btn-[a-zA-Z]*-[a-zA-Z]*-\)'`
 	unit="${filename//$m/}"
 
 	echo "$k -> icons/$w/$unit.png ($w x $h)"