dsc | 7 +++++++

diff --git a/dsc b/dsc
index ea17239295d7235207e670cf7bb6d018515cb9ae08ff55f04d322b0052f5853c..96f267ffd2c9f0618cf481f4a6f64a7a50ccf1dba9ec001604ce842b9dc728ea 100755
--- a/dsc
+++ b/dsc
@@ -44,6 +44,7 @@     $DSC_STASH  -- path to stashed/unsaved state
     $DSC_SAVED  -- path to committed/saved state
     $DSC_HASHERS -- "sha2-512 sha512" by default.
                     Newline-separated list of "hash-name cmd" pairs
+    $DSC_CSUM_ON_COMMIT=1 -- create $DSC_SAVED.csum file during commit
 
 There are two kinds of options:
     * array/list ones, which are identified with /*/ in "list"'s
@@ -350,6 +351,12 @@         exec sync
         file rename $Saved $Saved.bak
         file rename $tmp $Saved
         file delete -force $Saved.bak
+        if {[info exists env(DSC_CSUM_ON_COMMIT)]} {
+            exec {*}[list $argv0 export-raw | $argv0 csum >$Saved.csum.tmp]
+            file delete -force $Saved.csum
+            file rename $Saved.csum.tmp $Saved.csum
+            exec sync
+        }
     }
     csum {
         set hsh [list]