diff --git a/docs/ENVIRONMENT.md b/docs/ENVIRONMENT.md
index 791ba8dd129..2ba222d3a62 100644
--- a/docs/ENVIRONMENT.md
+++ b/docs/ENVIRONMENT.md
@@ -341,7 +341,7 @@ the journal instead of only when logging in debug mode.
 
 `systemd-sysusers`
 
-* `SOURCE_DATE_EPOCH` — if unset, the field of the date of last password change
+* `$SOURCE_DATE_EPOCH` — if unset, the field of the date of last password change
   in `/etc/shadow` will be the number of days from Jan 1, 1970 00:00 UTC until
   today. If `$SOURCE_DATE_EPOCH` is set to a valid UNIX epoch value in seconds,
   then the field will be the number of days until that time instead. This is to