diff --git a/generator/actions.ml b/generator/actions.ml
index 9e8f017dc..d75de8db9 100644
--- a/generator/actions.ml
+++ b/generator/actions.ml
@@ -8240,7 +8240,7 @@ See also C<guestfs_pwrite>." };
     ];
     shortdesc = "read part of a device";
     longdesc = "\
-This command lets you read part of a file.  It reads C<count>
+This command lets you read part of a block device.  It reads C<count>
 bytes of C<device>, starting at C<offset>.
 
 This may read fewer bytes than requested.  For further details