diff --git a/share/functions/__fish_posix_quote.fish b/share/functions/__fish_posix_quote.fish
new file mode 100644
index 000000000..729fae5ba
--- /dev/null
+++ b/share/functions/__fish_posix_quote.fish
@@ -0,0 +1,11 @@
+# localization: skip(private)
+function __fish_posix_quote
+    for arg in $argv
+        if set -l bareword (string match -r -- '^[-=\w]+$' $arg)
+            printf "%s " $bareword
+            continue
+        end
+        printf "'%s' " (printf %s $arg | string replace -a -- "'" "'\\''" |
+            string collect --no-trim-newlines)
+    end
+end
diff --git a/share/functions/fish_config.fish b/share/functions/fish_config.fish
index 9448d6feb..2700a2be7 100644
--- a/share/functions/fish_config.fish
+++ b/share/functions/fish_config.fish
@@ -190,8 +190,11 @@ function fish_config --description "Launch fish's web based configuration"
                         echo "Too many arguments" >&2
                         return 1
                     end
-                    # Write the current theme in .theme format, to stdout.
-                    set -L | string match -r (__fish_theme_variable_filter)
+                    # Write some of the current theme in .theme format, to stdout.
+                    for varname in (__fish_theme_variables)
+                        __fish_posix_quote $varname $$varname
+                        echo
+                    end
                 case '*'
                     echo "No such command: $cmd" >&2
                     return 1