Add sibling: new git helper script and alias

dotfiles/git-universe/before.gitconfig

@@ -27,5 +27,6 @@
   rb = rebase
   rbi = rebase --interactive
   rmv = remote --verbose
+  sibling = ! ~/.git-universe/bin/sibling
   st = status
   sh = show

dotfiles/git-universe/bin/sibling

@@ -0,0 +1,74 @@
+#!/bin/sh
+#
+# Take first subdir (or a subdir specified in a file) and consider
+# it a git repo dir.  Get its origin, exchange the last bit for
+# other project name and clone the other repo
+#
+# This is useful if you have a local dir where you store repos
+# for various projects from a common namespace that differ only
+# in last part of the remote URI.  Now all you need to do to
+# clone new one is "git sibling aproject".  The script will
+# do the rest for you including sniffing the URI.
+#
+# The script simply takes the first subdir.  In case this is not
+# OK for you (e.g. the dir id likely to be empty or contain
+# come "non-compliant" repos, you can specify path to the
+# other "template" repo in .git-universe-sibling file.
+#
+# Hint: regarding the "template" repo, you can easily create
+# a "fake" repo that would sit elsewhere, e.g.:
+#     $ mkdir .some/hidden/dir
+#     $ cd .some/hidden/dir
+#     $ git init
+#     $ git remote add origin ssh://our_server/projects/FAKE
+
+
+## cfgz
+#
+
+origin_name="origin"
+sibling_conf=".git-universe-sibling"
+
+
+## funz
+#
+
+rewrite_uri_to () {
+    # create a new remote URI based on current one
+    git remote -v \
+        | grep "^$origin_name" \
+        | grep "(fetch)$" \
+        | cut -f 2 \
+        | cut -d" " -f 1 \
+        | perl -pe "s|[^/]+$|$1|;"
+}
+
+
+## initz
+#
+
+project=$1
+
+if [ -f $sibling_conf ];
+then
+    sibling=$(cat $sibling_conf);
+else
+    sibling=$(find -maxdepth 1 -type d -name "[^.]*" | head -1)
+fi
+
+if [ -z "$sibling" ];
+then
+    echo "could not find older sibling" 1>&2
+    exit 1
+fi
+
+
+## body
+#
+
+pushd "$sibling" >/dev/null
+new_remote=$(rewrite_uri_to $project)
+popd >/dev/null
+
+echo \'git clone $new_remote\'
+git clone $new_remote