diff --git a/zshrc b/zshrc
index ae71caf45..d3fbc5998 100644
--- a/zshrc
+++ b/zshrc
@@ -151,6 +151,11 @@ if [[ "$OS_TYPE" == "FreeBSD" ]]; then
   fi
 fi
 
+if [[ "$OS_TYPE" == "Linux" ]]; then
+  LS_COMMAND=ls
+  dircolors_enable=1
+fi
+
 # enable ls colorization: 
 if [ "$TERM" != "dumb" ]; then
   if [[ "$dircolors_enable" == 1 ]]; then
@@ -202,7 +207,9 @@ alias grep="grep --color='always'"
 alias less='less -R'
 alias diff='colordiff'
 
+# sudo shell with "s"
+alias s='sudo -s -E'
 
-set modeline
-
+# don't require "rehash" after installing a package
+setopt nohashdirs