crontab.d/update.sh: Documentation update.

diff --git a/crontab.d/update.sh b/crontab.d/update.sh
index cfdcbcc5a3364562ac3b2b0555c06d2e94fbf3f2..ca08be1c080a5b18112fed33f602a6f6cd220280 100755 (executable)
--- a/crontab.d/update.sh
+++ b/crontab.d/update.sh
@@ -5,7 +5,7 @@
 #
 # An existing crontab entry not generated with this script is not overwritten.
 
-# Copyright (C) 2012  Simon Ruderich
+# Copyright (C) 2012-2013  Simon Ruderich
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -26,7 +26,8 @@ set -e
 
 HEADER_WARNING="# WARNING! DO NOT EDIT THIS FILE! #"
 
-# Don't overwrite existing crontab entries.
+# Don't overwrite existing crontab entries. Not race condition free but that
+# can't be helped.
 if crontab -l >/dev/null 2>&1; then
     if crontab -l | head -n3 | grep "^$HEADER_WARNING$" >/dev/null; then
         :
@@ -42,6 +43,7 @@ if test ! -d "$DIRECTORY" || test ! -O "$DIRECTORY"; then
     exit 1
 fi
 
+# `set -e` aborts when `mktemp` fails.
 CRONTAB=`mktemp --tmpdir="$DIRECTORY" update-crontab.XXXXXXXXXXXX`
 
 echo "###################################"  > "$CRONTAB"