diff --git a/install.sh b/install.sh
index 367a3a7..9a72a98 100755
--- a/install.sh
+++ b/install.sh
@@ -255,12 +255,27 @@ joinmarket_install ()
 {
     jm_pkgs=( 'jmbase' 'jmdaemon' 'jmbitcoin' 'jmclient' )
     for pkg in ${jm_pkgs[@]}; do
+        pip uninstall -y "${pkg/jm/joinmarket}"
         pushd "${pkg}"
-        pip install . || return 1
+        pip install ${develop_build:+-e} . || return 1
         popd
     done
 }
 
+parse_flags ()
+{
+    for flag in ${@}; do
+        case ${flag} in
+            --develop)
+                develop_build='1'
+                ;;
+            *)
+                echo "warning.  unknown flag : ${flag}" 1>&2
+                ;;
+        esac
+    done
+}
+
 main ()
 {
     jm_source="$PWD"
@@ -270,6 +285,10 @@ main ()
     export LD_LIBRARY_PATH="${LD_LIBRARY_PATH}:${jm_root}/lib"
     export C_INCLUDE_PATH="${C_INCLUDE_PATH}:${jm_root}/include"
 
+    # flags
+    develop_build=''
+    parse_flags ${@}
+
     if ! deb_deps_install; then
         echo "Dependecies could not be installed. Exiting."
         return 1
@@ -309,4 +328,4 @@ main ()
 
     from this directiry, to acticate virtualenv."
 }
-main
+main ${@}