support setting empty values (sanely) & removing support for

[apt.git] / debian / apt.cron.daily

diff --git a/debian/apt.cron.daily b/debian/apt.cron.daily
index 2616af1dd17fce4b2d94ca0e0d7e3f27726c8ba1..765dd4ae4164ea9eadbd932344645ff6d07ddfaf 100644 (file)
--- a/debian/apt.cron.daily
+++ b/debian/apt.cron.daily
@@ -3,7 +3,7 @@
 #
 # This file understands the following apt configuration variables:
 # Values here are the default.
-# Create /etc/apt/apt.conf.d/02periodic file to set your preference.
+# Create /etc/apt/apt.conf.d/10periodic file to set your preference.
 #
 #  Dir "/";
 #  - RootDir for all configuration files
@@ -34,14 +34,14 @@
 #  APT::Archives::MinAge "2"; (old, deprecated)
 #  APT::Periodic::MinAge "2"; (new)
 #  - Set minimum age of a package file. If a file is younger it
-#    will not be deleted (0=disable). Usefull to prevent races 
+#    will not be deleted (0=disable). Useful to prevent races
 #    and to keep backups of the packages for emergency.
 #
 #  APT::Archives::MaxSize "0"; (old, deprecated)
 #  APT::Periodic::MaxSize "0"; (new)
 #  - Set maximum size of the cache in MB (0=disable). If the cache
 #    is bigger, cached package files are deleted until the size
-#    requirement is met (the biggest packages will be deleted 
+#    requirement is met (the oldest packages will be deleted 
 #    first).
 #
 #  APT::Periodic::Update-Package-Lists "0";
@@ -68,6 +68,19 @@
 #      1:  progress report       (actually any string)
 #      2:  + command outputs     (remove -qq, remove 2>/dev/null, add -d)
 #      3:  + trace on            
+#
+#  APT::Periodic::RandomSleep "1800";
+#  - The apt cron job will delay its execution by a random
+#    time span between zero and 'APT::Periodic::RandomSleep'
+#    seconds.
+#    This is done because otherwise everyone would access the
+#    mirror servers at the same time and put them collectively
+#    under very high strain.
+#    You can set this to '0' if you are using a local mirror and
+#    do not care about the load spikes.
+#    Note that sleeping in the apt job will be delaying the
+#    execution of all subsequent cron.daily jobs.
+#
 
 check_stamp()
 {
@@ -91,7 +104,7 @@ check_stamp()
     stamp=$(date --date=$(date -r $stamp_file --iso-8601) +%s 2>/dev/null)
     if [ "$?" != "0" ]; then
         # Due to some timezones returning 'invalid date' for midnight on
-        # certain dates (eg America/Sao_Paulo), if date returns with error
+        # certain dates (e.g. America/Sao_Paulo), if date returns with error
         # remove the stamp file and return 0. See coreutils bug:
         # http://lists.gnu.org/archive/html/bug-coreutils/2007-09/msg00176.html
         rm -f "$stamp_file"
@@ -101,14 +114,14 @@ check_stamp()
     now=$(date --date=$(date --iso-8601) +%s 2>/dev/null)
     if [ "$?" != "0" ]; then
         # As above, due to some timezones returning 'invalid date' for midnight
-        # on certain dates (eg America/Sao_Paulo), if date returns with error
+        # on certain dates (e.g. America/Sao_Paulo), if date returns with error
         # return 0.
         return 0
     fi
 
     delta=$(($now-$stamp))
 
-    # intervall is in days, convert to sec.
+    # interval is in days, convert to sec.
     interval=$(($interval*60*60*24))
     debug_echo "check_stamp: interval=$interval, now=$now, stamp=$stamp, delta=$delta (sec)"
 
@@ -338,7 +351,7 @@ if test -r /var/lib/apt/extended_states; then
     fi
 fi
 
-# check apt-config exstance
+# check apt-config existence
 if ! which apt-config >/dev/null ; then
        exit 0
 fi
@@ -384,7 +397,7 @@ fi
 now=$(date +%s)
 
 # Support old Archive for compatibility.
-# Document only Periodic for all controling parameters of this script.
+# Document only Periodic for all controlling parameters of this script.
 
 UpdateInterval=0
 eval $(apt-config shell UpdateInterval APT::Periodic::Update-Package-Lists)