Add absolute path helpers

src/bin/dotify

@@ -31,6 +31,7 @@ shopt -s extglob
 # Helper functions
 #
 
+source "../lib/helpers/absolute-paths.sh"
 source "../lib/helpers/arguments.sh"
 source "../lib/helpers/trim.sh"
 

src/lib/helpers/absolute-paths.sh

@@ -0,0 +1,30 @@
+# Get absolute path to directory given file resides in.
+#
+# Example:
+#
+#   $ cd /tmp/foo-bar
+#   $ abs_dirname hello/world.txt
+#   /tmp/foo-bar/hello/world.txt
+#
+abs_dirname() {
+  local cwd="$(pwd)"
+  local path="$1"
+
+  while [ -n "$path" ]; do
+    cd "${path%/*}"
+    local name="${path##*/}"
+    path="$(resolve_link "$name" || true)"
+  done
+
+  pwd
+  cd "$cwd"
+}
+
+abs_path() {
+  local path="$1"
+  echo "$(cd "$(abs_dirname "$path")" && pwd)/$(basename "$path")"
+}
+
+resolve_link() {
+  $(type -p greadlink readlink | head -1) $1
+}