diff --git a/bootstrap/autostow.sh b/bootstrap/autostow.sh
index cbe0482..b7dd038 100755
--- a/bootstrap/autostow.sh
+++ b/bootstrap/autostow.sh
@@ -83,7 +83,10 @@ dryrun() {
 is_ignored() {
   IFS=":"
   for ign in $ignore; do
-    if [ "$ign" == "$1" ] || [ "$ign/" == "$1" ]; then
+    # it is either passed in through our environment variable
+    # or it starts with a _ which is ignored by default (that's the regex).
+    # (using herestring to avoid cat>grep)
+    if [ "$ign" = "$1" ] || [ "$ign/" = "$1" ] || grep -q -e '^_[[:alnum:]]\{1,\}' <<<"$1"; then
       return 0
     fi
   done
@@ -115,7 +118,9 @@ usage() {
     "" \
     "     -n | --dry-run  Do not invoke any operation but print out directories affected, simulating a dry-run." \
     "" \
-    "     -d     Remove dotfiles, by unlinking any directory found next to stow.sh using GNU stow." \
+    " Note, by default any directory starting with an underscore _directoryname will be ignored." \
+    " Additional folders to ignore can be set through the environment variable AUTOSTOW_IGNORED_DIRS " \
+    " using a colon-separated string: AUTOSTOW_IGNORED_DIRS=\"directories:to:ignore\"   " \
     "" \
     ""
 }