Make rewrite_uri actually work

dotfiles/gittum/bin/sibling

     exit 0
 }
 
-rewrite_uri_to () {
+rewrite_uri () {
+    local remote=$1
+    local to=$2
     # create a new remote URI based on current one
     git remote -v \
-        | grep "^$origin_name" \
+        | grep "^$remote" \
         | grep "(fetch)$" \
         | cut -f 2 \
         | cut -d" " -f 1 \
-        | perl -pe "s|[^/]+$|$1|;"
+        | perl -pe "s|[^/]+$|$to|;"
 }
 
 think() {
 #
 
 pushd "$sibling" >/dev/null
-new_remote=$(rewrite_uri_to $project)
+new_remote=$(rewrite_uri $remote_name $project)
 popd >/dev/null
 
+test -n "$new_remote" || die "no such remote at sibling: $new_remote at $sibling"
+
 think \'git clone $new_remote\'
 git clone $new_remote