My first script

pablowablo · 08-08-2004, 05:22 AM

It's very simple, just copies some of my files to my windows partition...

Tips are very much welcomed... Pls point out If I'm doing things wrongs or how I could improve this script... I'm still learning and just started reading up on shell scripting

Code:

#!/bin/bash

###############################
#  Script to copy my configuration files to my windows drive (in case I screw up 
#  Linux and be forced to reinstall :p
#  So far these are the only files I manually edited/created
#############################


if [ $# -eq 0 ];then 		#if no parameter then use default directory
	bkup_dir="/mnt/habo/Linux_Backups"
elif [ $# -ne 1 ];then	 	#script accepts only 1 parameter
		echo Too many parameters.. exiting
		exit
else				#use given directory
	bkup_dir=$1
fi

if ! [ -d $bkup_dir ];then	#if directory doesn't exist then create 
	echo Creating directory $bkup_dir...
	if mkdir $bkup_dir;then
		echo $bkup_dir successfully created
	else
		echo Cannot create $bkup_dir...exiting
		exit
	fi
fi

#Copy the files to backup directory
if cp /etc/fstab $bkup_dir/fstab.bak &&
   cp /etc/auto.master $bkup_dir/auto.master.bak &&
   cp /etc/auto.pablo $bkup_dir/auto.pablo.bak; then
	echo Configuration files successfully copied.
else
	echo Could not copy configuration files!
fi

Disillusionist · 08-08-2004, 06:57 AM

The code looks fine to me, what happens when you run it?

If you are creating directorys and files on a Windows mount point, you may well run into permission issues.

A couple of suggestions to improve the script.

1. Instead of testing the number of parameters used, as you are only wanting the first paramer try the following:

bkup_dir=${1:-/mnt/habo/Linux_Backups}

This will set the variable bkup_dir to the first parameter $1 if it exists, or the default of /mnt/habo/Linux_Backups if $1 doesn't exist.

2. When you call exit add a non zero number to the end. This way, if you call this script from another script you can check the exit value to see if it worked an exit code of 0 is the default value for a script or program that worked.

Happy learning!

pablowablo · 08-08-2004, 07:13 AM

hey thanks! I followed your advice and it still works.. tho I do not really know the syntax of that line

hehe Ima do some more researching.... Thanks for the advice, really appreciate it..

Oh btw, the script runs ok

I already set the permission on my Windows drive coz I always use it as a normal user

hehe right now out how to execute this script every 24 hrs using cron...

Disillusionist · 08-08-2004, 07:48 AM

Cron uses a text file to schedule tasks based on 6 parameters separated by spaces.

Parameters
1 the minute you want the script to run (0-59) or * for every minute
2 The hour you want (0-23) or * for every hour
3 The day of the month (0-31) or *
4 The month (1-12) or *
5 The day of the week (0-6) or * 0=sunday
6 The script (and any parameters) you want to run

You can make a backup copy of your crontab file by running:

crontab -l > /usr/cron_save

Then edit by running:

crontab -e

Insert a line, and add your command to run every 24 hours

Code:

# Comment for my script
00 12 * * * /usr/local/myscript > /tmp/myscript.log 2>&1

This would run /usr/local/myscript every day at 12:00 and create a log of the latest result in /tmp/myscript.log

If you need to restore your original crontab file then run:

crontab /usr/cron_save

pablowablo · 08-08-2004, 10:05 AM

Hmmm do I have to restart the cron daemon to test my script?

I added this line to my crontab

Code:

2 23 * * * /home/pablo/pbkup > /tmp/myscript.log 2>&1

But nothing happened, myscript.log was not created...

pablowablo · 08-08-2004, 10:11 AM

Never mind it works now... I used this instead

Code:

0 22 * * * sh /home/pablo/Pablo\ Scripts/pbkup > /dev/null

Thanks for your help again!

frob23 · 08-08-2004, 10:25 AM

Just so you know... you don't need to restart cron to run anything after you make changes. The program crontab lets cron know to reread the file for the user who invoked it.

That way little peon users can have crontab files for themselves and they don't need to wait for the system to reboot or cron to be restarted. This is one of the many reasons we use crontab instead of just editing the physical file with any old text editor.