ENH: improve foamEtcFile handling (-prefix, -version options)

- This lets foamExec use foamEtcFile as well, but debian packaging
  still needs some work

bin/foamEtcFile

@@ -39,8 +39,6 @@
 #     @endverbatim
 #
 #-------------------------------------------------------------------------------
-unset listOpt quietOpt
-
 usage() {
     [ "$quietOpt" = true ] && exit 1
 
@@ -53,7 +51,11 @@ Usage: ${0##*/} [OPTION] fileName
 options:
   -list             list the directories to be searched
   -mode <mode>      any combination of u(user), g(group), o(other)
+  -prefix <dir>     specify an alternative installation prefix
+                        (default: $WM_PROJECT_INST_DIR)
   -quiet            suppress all normal output
+  -version <ver>    specify an alternative OpenFOAM version
+                        (default: $WM_PROJECT_VERSION)
   -help             print the usage
 
   Locate user/group/shipped file with semantics similar to the
@@ -75,6 +77,13 @@ USAGE
 # default mode is 'ugo'
 mode=ugo
 
+# default prefix/version correspond to the active values,
+# but could also extract from the $0 value.
+prefix="$WM_PROJECT_INST_DIR"
+version="$WM_PROJECT_VERSION"
+
+
+unset listOpt quietOpt
 # parse options
 while [ "$#" -gt 0 ]
 do
@@ -100,10 +109,20 @@ do
         esac
         shift 2
         ;;
+    -p | -prefix)
+        [ "$#" -ge 2 ] || usage "'$1' option requires an argument"
+        prefix="$2"
+        shift 2
+        ;;
     -q | -quiet)
         quietOpt=true
         shift
         ;;
+    -v | -version)
+        [ "$#" -ge 2 ] || usage "'$1' option requires an argument"
+        version="$2"
+        shift 2
+        ;;
     -*)
         usage "unknown option: '$*'"
         ;;
@@ -121,21 +140,21 @@ fileName="$1"
 unset dirList
 case "$mode" in
 *u*)  # user
-    dirList="$dirList $HOME/.${WM_PROJECT:-OpenFOAM}/$WM_PROJECT_VERSION"
+    dirList="$dirList $HOME/.${WM_PROJECT:-OpenFOAM}/$version"
     dirList="$dirList $HOME/.${WM_PROJECT:-OpenFOAM}"
     ;;
 esac
 
 case "$mode" in
 *g*)  # group
-    dirList="$dirList $WM_PROJECT_INST_DIR/site/$WM_PROJECT_VERSION"
-    dirList="$dirList $WM_PROJECT_INST_DIR/site"
+    dirList="$dirList $prefix/site/$version"
+    dirList="$dirList $prefix/site"
     ;;
 esac
 
 case "$mode" in
-*o*)  # other
-    dirList="$dirList $WM_PROJECT_DIR/etc"
+*o*)  # other (shipped)
+    dirList="$dirList $prefix/${WM_PROJECT:-OpenFOAM}-$version/etc"
     ;;
 esac
 set -- $dirList