add a hook to (try to) spool every outgoing mail

diff --git a/.mutt/sendmail-checks.d/zzz_add-spool-bcc b/.mutt/sendmail-checks.d/zzz_add-spool-bcc
new file mode 100755 (executable)
index 0000000..12b1568
--- /dev/null
+++ b/.mutt/sendmail-checks.d/zzz_add-spool-bcc
@@ -0,0 +1,19 @@
+#!/bin/sh
+#
+# zzz_add-spool-bcc — add a spool mailbox as bcc recipient (runs last)
+#
+# Write a copy of the temporary file to a spool Maildir.
+#
+# Copyright © 2010 martin f. krafft <madduck@madduck.net>
+# Released under the terms of the Artistic Licence 2.0
+#
+set -eu
+
+SPOOL_MAILDIR=$HOME/mail/spool
+
+if ! cp -n "$1" "$SPOOL_MAILDIR/cur/${1##*/}:2,S"; then
+  echo >&1 "W: failed to spool message file '$1'."
+  TMPFILE=$(tempfile -p mutt-sendmail -s .msg)
+  cat "$1" > "$TMPFILE"
+  echo >&1 "W: leaving a copy in '$TMPFILE'…"
+fi