diff --git a/runtime/autoload/dist/script.vim b/runtime/autoload/dist/script.vim
index b55fab3..0079f4b 100644
--- a/runtime/autoload/dist/script.vim
+++ b/runtime/autoload/dist/script.vim
@@ -4,7 +4,7 @@
 # Invoked from "scripts.vim" in 'runtimepath'
 #
 # Maintainer:	Bram Moolenaar <Bram@vim.org>
-# Last Change:	2023 May 06
+# Last Change:	2023 Jun 08
 
 export def DetectFiletype()
   var line1 = getline(1)
@@ -44,7 +44,7 @@
   elseif line1 =~ '^#!\s*[^/\\ ]*\>\([^/\\]\|$\)'
     name = substitute(line1, '^#!\s*\([^/\\ ]*\>\).*', '\1', '')
   else
-    name = substitute(line1, '^#!\s*\S*[/\\]\(\i\+\).*', '\1', '')
+    name = substitute(line1, '^#!\s*\S*[/\\]\(\f\+\).*', '\1', '')
   endif
 
   # tcl scripts may have #!/bin/sh in the first line and "exec wish" in the
@@ -197,6 +197,10 @@
   elseif name =~ 'guile'
     setl ft=scheme
 
+    # Nix
+  elseif name =~ 'nix-shell'
+    setl ft=nix
+
   endif
 enddef
 
diff --git a/src/testdir/test_filetype.vim b/src/testdir/test_filetype.vim
index d5e0038..ae76969 100644
--- a/src/testdir/test_filetype.vim
+++ b/src/testdir/test_filetype.vim
@@ -852,6 +852,7 @@
     expect: [['#!/path/expect']],
     gnuplot: [['#!/path/gnuplot']],
     make:   [['#!/path/make']],
+    nix:    [['#!/path/nix-shell']],
     pike:   [['#!/path/pike'],
             ['#!/path/pike0'],
             ['#!/path/pike9']],
@@ -902,6 +903,7 @@
     scheme: [['#!/usr/bin/env VAR=val --ignore-environment scheme']],
     python: [['#!/usr/bin/env VAR=val -S python -w -T']],
     wml: [['#!/usr/bin/env VAR=val --split-string wml']],
+    nix: [['#!/usr/bin/env nix-shell']],
   }
 enddef
 
diff --git a/src/version.c b/src/version.c
index 90331ed..bad9e54 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1620,
+/**/
     1619,
 /**/
     1618,