diff --git a/ruby/shell/word_expander.rb b/ruby/shell/word_expander.rb
index aaf30a3..ca053f1 100644
--- a/ruby/shell/word_expander.rb
+++ b/ruby/shell/word_expander.rb
@@ -68,7 +68,12 @@ module Shell
         found_glob_char = word && word =~ /[*?\[]/ # must be unquoted
         # Expand tildes at the beginning of unquoted words.
         if word && at_word_start
-          field.sub!(/^~/, Dir.home)
+          field.sub!(/^~([^\/]*)/) do
+            user = Regexp.last_match(1)
+            user.empty? ? Dir.home : Dir.home(user)
+          rescue ArgumentError
+            "~#{user}"
+          end
         end
         at_word_start = false
         if sep