diff --git a/Library/Homebrew/cmd/shellenv.sh b/Library/Homebrew/cmd/shellenv.sh
index 193924f27c..4355ce52ea 100644
--- a/Library/Homebrew/cmd/shellenv.sh
+++ b/Library/Homebrew/cmd/shellenv.sh
@@ -20,8 +20,8 @@ homebrew-shellenv() {
       echo "setenv HOMEBREW_CELLAR $HOMEBREW_CELLAR;"
       echo "setenv HOMEBREW_REPOSITORY $HOMEBREW_REPOSITORY;"
       echo "setenv PATH $HOMEBREW_PREFIX/bin:$HOMEBREW_PREFIX/sbin:\$PATH;"
-      echo "setenv MANPATH $HOMEBREW_PREFIX/share/man:\$MANPATH;"
-      echo "setenv INFOPATH $HOMEBREW_PREFIX/share/info:\$INFOPATH;"
+      echo "setenv MANPATH $HOMEBREW_PREFIX/share/man\`[ \${?MANPATH} == 1 ] && echo \":\${MANPATH}\"\`:;"
+      echo "setenv INFOPATH $HOMEBREW_PREFIX/share/info\`[ \${?INFOPATH} == 1 ] && echo \":\${INFOPATH}\"\`;"
       ;;
     *)
       echo "export HOMEBREW_PREFIX=\"$HOMEBREW_PREFIX\";"