--- a/rc/tcsh	Tue Nov 08 11:56:49 2011 +0700
+++ b/rc/tcsh	Tue Nov 08 11:59:49 2011 +0700
@@ -1,5 +1,23 @@
 #!/usr/bin/env tcsh
-[ -e "${HOME}/.ecos_tcsh.before" ] && source "${HOME}/.ecos_tcsh.before"
+
+# Ensures it's tcsh
+if ( ! $?tcsh ) then
+  exit
+endif
+
+# Ensures this script is running on terminal. Otherwise exit immediately.
+if ( ! $?prompt ) then
+  exit
+endif
+
+# Ensures we're not loading this script again.
+if ( ! $?ecos_tcsh_loaded ) then
+  set ecos_tcsh_loaded="yes"
+else
+  exit
+endif
+
+test -f "${HOME}/.ecos_tcsh.before" && source "${HOME}/.ecos_tcsh.before"
 umask 22
 limit coredumpsize 0
 
@@ -78,7 +96,7 @@
   case OpenBSD:
     set path=(${path} /usr/local/{bin,sbin})
     setenv LSCOLORS ExGxFxdxCxegedabagExEx
-    [ "${iscolor}" -eq 1 ] && setenv TERM xterm-256color
+    test "${iscolor}" -eq 1 && setenv TERM xterm-256color
     ( which colorls ) > /dev/null && alias ls colorls -FG
   breaksw
   case DragonFly:
@@ -88,7 +106,7 @@
   breaksw
   case SunOS:
     set path=(${path} /usr/{gnu,csw,xpg4}/{bin,sbin})
-    [ -x /usr/gnu/bin/ls ] && alias ls /usr/gnu/bin/ls ${gnuls_opts}
+    test -x /usr/gnu/bin/ls && alias ls /usr/gnu/bin/ls ${gnuls_opts}
   breaksw
   case Linux:
     alias ls ls ${gnuls_opts}
@@ -99,6 +117,6 @@
 
 ( which vim ) > /dev/null && alias vi vim && setenv EDITOR vim
 
-[ -e "${HOME}/.ecos_tcsh.after" ] && source "${HOME}/.ecos_tcsh.after"
+test -f "${HOME}/.ecos_tcsh.after" && source "${HOME}/.ecos_tcsh.after"
 
-[ -x "/usr/games/fortune" ] && "/usr/games/fortune"
+test -x "/usr/games/fortune" && "/usr/games/fortune"