Africa's OSS/Linux All Blogs

Linux server is better than Swiss army knife. Using pipes you can join commands together to process and transform data.

Task:

Automatically backup entire folder to encrypted file and upload in secure manner to backup server using minimum of disk space.

Code:

#
# install as cronjob, must escape any % as \% otherwise it becomes newline
#
tar cvf - /home/tom | gpg --no-tty --passphrase-file pass.txt -c - | ssh user@backup.com "cat > tom.tar.gpg"

Explanation:
--no-tty is required for cronjob as there is no tty attached during execution
pass.txt will contain your symmetrical password

#
# create tarball containing entire folder and send output to stdout
#
tar cvf - /home/tom

#
# read from stdin and encrypt data stream using pass phrase in file pass.txt
#
| gpg --no-tty --passphrase-file pass.txt -c -

#
# read from stdin data stream and send via secure shell to backup server as tom.tar.gpg
#
| ssh user@backup.com "cat > tom.tar.gpg"

for more info try

man tar
man gpg
man ssh

If you are lucky owner of PS3 system and got tired of game playing then you can try Linux using PS3 hardware. Yellow Dog Linux is specifically made for PS3 and is easy to install and use. Being Linux you can start to write and compile your own software that runs on PS3 console

SSH lets you work on remote server on another continent. Often you need to launch process which will run for some time. One option is to use crontab, second option is to use nohup command. When you launch process and logoff or loose your connection, this process will be terminated. nohup will prevent process being terminated so you can logoff safely, example

nohup ./myprocess &>myprocess.out &

standard output and error will be redirected to myprocess.out file, ampersand at the end makes it a background process so you can execute other commands like top to see cpu and memory usage

to see output from myprocess run

tail -f myprocess.out

Linux rocks !

Knoppix distribution has its own book now

One interesting aspect is that you can create your own distribution based on Knoppix

Check out Knoppix Remastering to find out the secret

Event was a full success
Lots of Linux cds were given away , I got a whole stack to try them out
Interesting discussion session about FOSS and how to promote it better
Best of all was FREE food & drinks !
Well done to organizers