dot/profile: Add a new function to export a variable only if it's defined.

This is useful for pathish variables: if they're exported then they're
set to empty, which implies the current directory.

diff --git a/dot/profile b/dot/profile
index 6730a25..2d597bf 100644 (file)
--- a/dot/profile
+++ b/dot/profile
@@ -57,6 +57,17 @@ __mdw_setconf () {
   fi
 }
 
+## __mdw_export_if_defined VAR ...
+##
+## If VARs are defined, then export them.
+__mdw_export_if_defined () {
+  local var t
+  for var in "$@"; do
+    eval t=\${$var+t}
+    case $t in t) export $var ;; esac
+  done
+}
+
 ###--------------------------------------------------------------------------
 ### Other preliminaries.