View Full Version : I'm looking a guide on writing shell scripts.

April 30th, 2007, 12:56 AM
I'm looking for a guide on writing a backup shell script. Does anyone know of a guide or a site I can go to for help on writing a backup script? Thanks for the replys.

April 30th, 2007, 12:57 AM
Shell scripts are just terminal command so any tutorial should do since I assume all your going to be doing is copying from one location to another.

any on google should be good

Unless I dont understand your Q

April 30th, 2007, 12:59 AM
Well, what should I have in a backup script? Just tar like say my home dir and backup? And is there a way to have it run like once a month or something?

April 30th, 2007, 01:05 AM
#Use crontab to do it monthly maybe? The crontab wiki is very well done.

#Then maybe make a script for your crontab to execute like this:

rsync -avF /data/ /backup/
Make sure to test whatever command you're gonna use if you plan on using crontab because you wouldn't want sometime to fail a month from now. n_n

Or if you want you could just execute this script on startup:

if [ "$(date +%d)" == "01" ]; then
rsync -avF /data/ /backup/
Just replace the rsync command with one that works for you.

April 30th, 2007, 01:11 AM
So what does the rsync -avF /data/ /backup/ do? I'm trying to learn.

April 30th, 2007, 01:12 AM
man rsync should give you all the info you need

April 30th, 2007, 01:21 AM
So what does the rsync -avF /data/ /backup/ do? I'm trying to learn.

What I always do is test it on a random folder like this:

dirname=$RANDOM$RANDOM; mkdir $dirname; cd $dirname; for ((n=0;n<5;n++)); do mkdir -p $RANDOM/$RANDOM; done; find . -type d | while read dir; do for ext in .jpg .png .exe .sh .py .pl .rb .cpp .txt; do echo "0101011101" > $dir/$RANDOM$ext; done; done; cd ..; echo "Created \"$dirname\""
After executing the above commands you'll have a folder with a random name that looks like this:

10945.exe 1279.txt 13282 13454 22350.cpp 2652.png 27370.sh 29309 30941.jpg 31270.py 4570 6027.rb 7580.pl 8190Which is just a folder with a bunch of random filenames each with some text in them!

Then you can play around by trying to move those files with rsync or whatever. Just be careful.

April 30th, 2007, 01:40 AM
this site has helped me allot, i hopes it serves you well also.. http://tldp.org/LDP/abs/html/

as for the backup script looking on what has already been poseted i couldn't add anything new to it.

April 30th, 2007, 01:45 AM
The reason rsync is good is because once you've backed up your files, it won't keep backing up the same files unless they have changed. This is enormously time saving.

The reason tar is good is because it does compression in combination with compression (the z option in gzip).

If you have the space, go with rsync.