New Zealand Linux

So, i want to often print things, however rarely am i at home to print, and by the time i get there i forget entirely about it. This is something i did one sunday evening to get printing on pretty much every device in the house to my home printer, at home or at work, or even on the road!

First of all, i setup myself a dropbox account (which is free). This is a file sharing ‘cloud’ style service which is fairly well known and popular.
I installed dropbox on my phone, my iPod touch, Work PC, Home Laptops or other computers and pretty much everything that supported it.

I used these Step by Step instructions to set it up on my gateway (which also has the printer attached) via a command line interface http://wiki.dropbox.com/TipsAndTricks/TextBasedLinuxInstall#Step-by-stepversion.

Once i had it mounted on the gateway/printing box, i ran the following commands

cd ~/Dropbox/
mkdir printer
cd printer
mkdir new done

This gives me a directory structure to work with for printing. The idea was to have a script poll the ‘new’ directory, and anything in there got sent to the printer, then moved to the ‘done’ directory. Should it not print correctly i can grab it from the done dir and retry later on.
I wrote a script named ‘script.sh’ and looked like this

#!/bin/bash
for file in `ls /home/velofille/Dropbox/printer/new/`
do lp -d laser /home/velofille/Dropbox/printer/new/$file  | mail -s "Print Job"  liz@mydomain.com
mv /home/velofille/Dropbox/printer/new/$file /home/velofille/Dropbox/printer/done/
done

chmod +x script.sh

I ran a few tests to make sure this worked ok, and sorted out a few printer driver errors. Once i had that working nicely, i added the pipe to my email address so i could confirm it printed (and any errors), then setup a crontab
*/5 * * * * /home/velofille/Dropbox/printer/script.sh >/dev/null 2>&1

That’s pretty much it in a nutshell, not overly complex or hard, the main thing will be making sure the Dropbox stays up and going.
To do this, i have the following shell script called checkdropbox.sh

#!/bin/sh
SERVICE='/home/velofille/.dropbox-dist/dropbox'
 
if ! ps ax | grep -v grep | grep $SERVICE > /dev/null
then
/home/velofille/.dropbox-dist/dropbox &
echo "$SERVICE is not running! Had to restart it" | mail -s "$SERVICE down" liz@mydomain.com
fi

chmod +x checkdropbox.sh

I then also put another crontab exactly the same as the printer one to run this

*/5 * * * * /home/velofille/bin/checkdropbox.sh >/dev/null 2>&1

Now i can print from pretty much anywhere in the world by simply dropping a file into a dropbox directory , then have an emailed report when that printed!

I love Backups!
This one is for a daily dump of the database, rolling over every 10 days

Put the following into a file in /etc/cron.daily/postgres-backup

#!/bin/bash
DIR=/backup/pgsql
FTPUSR=yourusername
FTPPASS=yourftppass
FTPHOST=yourftphost
 
LIST=$(su - postgres -c "/usr/bin/psql -lt" |/usr/bin/awk '{ print $1}' |/bin/grep -vE '^-|:|^List|^Name|template[0|1]')
DATE=$(/bin/date '+%Y%m%d');
TENDAY=$(/bin/date -d'10 days ago' '+%Y%m%d');
/bin/mkdir -p $DIR/$DATE/
/bin/chown postgres:postgres $DIR/$DATE/
 
for d in $LIST
do
su - postgres -c "/usr/bin/pg_dump $d | gzip -c > $DIR/$DATE/$d.sql.gz"
done
 
rm -rf $DIR/$TENDAY/
/usr/bin/lftp -u "$FTPUSR,$FTPPASS" ${FTPHOST} -e "set ftp:ssl-protect-data true;mirror --reverse --delete $DIR/ /; exit"

Everyone wants to back up right? Well you will once you have totally lost the last years worth of work on a website and somebody breaks things severely!

Heres a quick and nasty backup HOWTO.

Database Dumps

mysqldump -u root -p mydatabase > mydatabase.sql

This dumps a database into a file, you can modify this to dump it offsite using ssh with this command.

su postgres -c "pg_dumpall" > pgdatabase.psql

If you use postgres you can change this to something like this

mysqldump -u root -p mydatabase > mydatabase.sql | ssh username@backup.comain.com “dd of=mydatabase.sql”

If you want to dump the entire database you can use

mysqldump -A -u root -p >entiredatabase.sql

This may take some time. To put this in a shell script and dump multiple copies and keep track of things you can use something similar to this

date=`date +%m-%h-%Y`

mysqldump -A -u root -p >${date}-fulldatabase.sql

This will expand to dump it into something like

06-Jun-2009-fulldatabase.sql

File Backup

FTP

To run a regular interactive FTP session:

lftp -u 'username,password' backup.yourdomain.com

To backup one or more files:

lftp -u 'username,password' backup.yourdomain.com -e "set ftp:ssl-protect-data true; mput /local/dir/files* /remotedir; exit"

You need to set ftp:ssl-protect-data else you will not be able to store the file. If you want to make this a default option, add it to the lftp.conf file. e.g. :

grep -qai "set ftp:ssl-protect-data true" /etc/lftp.conf || echo "set ftp:ssl-protect-data true" >> /etc/lftp.conf

To restore a file from the FTP server to your Machine:

lftp -u 'username,password' backup.yourdomain.com -e "set ftp:ssl-protect-data true;mget /remotedir/files* -O /localdir; exit" .

The -O option is not required it you wish to store to the current local directory.

To mirror a whole directory to the FTP server:

lftp -u 'username,password' backup.yourdomain.com -e "set ftp:ssl-protect-data true;mirror --reverse /local/dir/name remotedirname; exit" .

--reverse means that the ‘mirroring’ is going in the reverse direction than ‘normal’. i.e. from your server to the backup server. If you run man lftp there are a few other options to choose from. e.g. --delete to delete files on the backup server that do not exist locally. Or --continue to continue a mirror job. Or --exclude files to exclude certain files from the transfer.

To restore a whole directory from the FTP server to your machine:

lftp -u 'username,password' backup.yourdomain.com -e "set ftp:ssl-protect-data true;mirror remotedirname /local/dir/name;exit"

To create a nightly cronjob that uploads a directory to the backup FTP server, create a /etc/crond.daily/ftpbackup file like this:

#!/bin/bash
lftp -u 'username,password' backup.yourdomain.com -e "set ftp:ssl-protect-data true;mirror --reverse /local/dir/name remotedirname;exit" > /dev/null

Run

chmod +x /etc/cron.daily/ftpbackup .

Then check the files have been mirrored as you expect the next day.

Rsync

Rsync is a better option in some ways as it checks the MD5 of files and updates them if they are out of date, rather than re-copying the entire lot. Short but easy shell script to copy things over

#!/bin/bash
EXCLUDE=” –exclude *.tmp \
–exclude *.temp”
USER=username
HOST=backup.domain.com
BACKUPPATH=/backups

rsync –archive -vv –rsh=ssh $EXCLUDE $USER@$HOST:/etc/ $BACKUPPATH/$HOST/etc

Rdiff-backup

This is better again than rsync as it does versioning control and only backs up the difference in files.

To backup files

rdiff-backup /some/local-dir hostname.net::/whatever/remote-dir

To restore

rdiff-backup --restore-as-of now host.net::/remote-dir/file local-dir/file
rdiff-backup -r now host.net::/remote-dir/file local-dir/file

The -r command is the same as –restore-as-of

The main advantage of rdiff-backup is that it keeps version history. This command restores host.net::/remote-dir/file as it was 10 days ago into a new location /tmp/file .

rdiff-backup -r 10D host.net::/remote-dir/file /tmp/file

Other acceptable time strings include 5m4s (5 minutes and 4 seconds) and 2002-03-05 (March 5th, 2002). For more information, see the TIME FORMATS section of the manual page.

More examples can be found at http://www.nongnu.org/rdiff-backup/examples.html

This tutorial was compiled from several others, and props go out to http://rimuhosting.com and http://www.howtoforge.com