screen setup: create sym link with relative path

setup

@@ -1,9 +1,16 @@
 #!/bin/bash
 
-dt=$(date -u +'%Y-%m-%dT%H.%M.%SZ')
+# relpath
+source ../bash/functions 
 
-cd "$( dirname "$0" )"
+link_path="$HOME/.screenrc"
+target_name="screenrc"
 
-mv ~/.screenrc ~/.screenrc.$dt
-ln -s `pwd`/screenrc ~/.screenrc
+script_dir="$( dirname "${BASH_SOURCE[0]}" )"
+target_path="$( relpath "${script_dir}/${target_name}" "$(dirname "${link_path}")" )"
 
+if [ -e "${link_path}" ]; then
+    mv --backup=numbered "$link_path" "${link_path}.old"
+fi
+
+ln -s "$target_path" "$link_path"