[Android Software/Hacking General [Developers Only]] mcbyte_it:
There are many ROMs that include the ZipAlign or SQLite3 vacuum on boot, but these command are not really needed to run on EVERY boot, once every few days can be enough, so I came out with this script.

To run it, you need to have busybox with the stat applet (should be there always), which gives information about a file, including last modification date.

This is done is by checking the last modification date on a file, which is touched or changed only when the main script is executed.

Currently I modified the ZipAlign and SQLite vacuum in my own rom to use this technique, and they seem to work fine. The monitored file is the log of the operation done, which is stored in the /data/ directory

ZipAlign on Boot:

#!/system/bin/sh
# Automatic ZipAlign by Wes Garner
# ZipAlign files in /data that have not been previously ZipAligned (using md5sum)
# Thanks to oknowton for the changes

# Changelog:
# 1.0 (11/30/09) Original
# 1.1 (12/01/09) Switched to zipalign -c 4 to check the apk instead of MD5 (oknowton)
# 1.2 (06/01/13) Run the main script only once every N days (default 7 days, 1 week) (mcbyte_it)

[COLOR="DarkRed"]LOG_FILE=/data/zipalign.log
#Interval between ZipAlign runs, in seconds, 604800=1 week
RUN_EVERY=604800

# Get the last modify date of the Log file, if the file does not exist, set value to 0
if [ -e $LOG_FILE ]; then
LASTRUN=`stat -t $LOG_FILE | awk '{print $14}'`
else
LASTRUN=0
fi;

# Get current date in epoch format
CURRDATE=`date +%s`

# Check the interval
INTERVAL=$(expr $CURRDATE - $LASTRUN)

# If interval is more than the set one, then run the main script
if [ $INTERVAL -gt $RUN_EVERY ];
then[/COLOR]
[COLOR="Green"]	if [ -e $LOG_FILE ]; then
rm $LOG_FILE;
fi;

echo "Starting Automatic ZipAlign $( date +"%m-%d-%Y %H:%M:%S" )" | tee -a $LOG_FILE;
for apk in /data/app/*.apk ; do
zipalign -c 4 $apk;
ZIPCHECK=$?;
if [ $ZIPCHECK -eq 1 ]; then
echo ZipAligning $(basename $apk) | tee -a $LOG_FILE;
zipalign -f 4 $apk /cache/$(basename $apk);

if [ -e /cache/$(basename $apk) ]; then
cp -f -p /cache/$(basename $apk) $apk | tee -a $LOG_FILE;
rm /cache/$(basename $apk);
else
echo ZipAligning $(basename $apk) Failed | tee -a $LOG_FILE;
fi;
else
echo ZipAlign already completed on $apk | tee -a $LOG_FILE;
fi;
done;
echo "Automatic ZipAlign finished at $( date +"%m-%d-%Y %H:%M:%S" )" | tee -a $LOG_FILE;[/color]
[COLOR="DarkRed"]fi[/COLOR]

SQLite3 vacuum:

#!/system/bin/sh
# ========================================
# init.d script for McByte jkSGS3
# ========================================

# SQLite database vaccum

# Frequent inserts, updates, and deletes can cause the database file to become fragmented - where data for a single table or index is scattered around the database file.
# Running VACUUM ensures that each table and index is largely stored contiguously within the database file.
# In some cases, VACUUM may also reduce the number of partially filled pages in the database, reducing the size of the database file further.
# sqlite3 binary in /system/xbin is required!

# Changelog
# v1.0 - (??/??/????) - original version
# v1.1 - (06/01/2013) - run only every X seconds, default = 1 week (mcbyte_it)
#

[COLOR="DarkRed"]# Log file location
LOG_FILE=/data/sqlite.log

#Interval between SQLite3 runs, in seconds, 604800=1 week
RUN_EVERY=604800

# Get the last modify date of the Log file, if the file does not exist, set value to 0
if [ -e $LOG_FILE ]; then
LASTRUN=`stat -t $LOG_FILE | awk '{print $14}'`
else
LASTRUN=0
fi;

# Get current date in epoch format
CURRDATE=`date +%s`

# Check the interval
INTERVAL=$(expr $CURRDATE - $LASTRUN)

# If interval is more than the set one, then run the main script
if [ $INTERVAL -gt $RUN_EVERY ];
then[/COLOR]
[COLOR="Green"]if [ -e $LOG_FILE ]; then
rm $LOG_FILE;
fi;

echo "SQLite database VACUUM and REINDEX started at $( date +"%m-%d-%Y %H:%M:%S" )" | tee -a $LOG_FILE;

for i in `busybox find /d* -iname "*.db"`; do
/system/xbin/sqlite3 $i 'VACUUM;';
resVac=$?
if [ $resVac == 0 ]; then
resVac="SUCCESS";
else
resVac="ERRCODE-$resVac";
fi;

/system/xbin/sqlite3 $i 'REINDEX;';
resIndex=$?
if [ $resIndex == 0 ]; then
resIndex="SUCCESS";
else
resIndex="ERRCODE-$resIndex";
fi;
echo "Database $i: VACUUM=$resVac REINDEX=$resIndex" | tee -a $LOG_FILE;
done

echo "SQLite database VACUUM and REINDEX finished at $( date +"%m-%d-%Y %H:%M:%S" )" | tee -a $LOG_FILE;[/COLOR]
[COLOR="DarkRed"]fi;[/COLOR]