Learn Unix Shell Scripting Training with Free Lessons & Tips

disk_check_advance.sh
#!/bin/ksh
var=`df -a|grep home|tail -1|awk '{print $3}'`
HOST=`hostname`
echo $var1
if [ $var -le 3000000 ]; then
df -h|grep home >data
# du -s /home/* 2>/dev/null| sort -rn |head -20>>data
# cat data|
# mail -s "Alert: Almost out of disk space on $HOST" umesh.prasad@fedex.com
while read line; do

ED=`echo $line|cut -d "/" -f3`
ID=`echo $line|cut -d "/" -f3|cut -c1`

if [ "$ID" == "f" ]
then

ID1=`echo $ED|cut -c2-`
`echo $line | mail -s "Alert:Almost out of Disk space on $HOST" $ID1@fedex.com`
else
ID1=`echo $ED|cut -c3-`
`echo $line | mail -s "Alert:Almost out of Disk space on $HOST" $ID1@fedex.com`
fi
done < data
fi

Bash scripting can be abale to do what a c programming language can do.It doesnt have OOPS properties . As we have other languages with wider functionalities like perl and python people are not relaying on Bash scripting .Even when the data is more some times Bash scrpting behaves odd as per my personal experience

I would like to answer this from Unix perspective.

I would share a couple of experience where I saw the things went messy.

The 1st and formost thumb rule is to avoid use of find and rm in your shell script eventhough you are removing the perticular file set from a specific directory because when you are doing the trouble shooting from developer's work area then it would remove the files recursively and it would take time to realise what went wrong.

Point 2) Always have time to time backup of .ssh directory where you store the public or private keys as this is the most critical directory where you maintain server connectivity which may impact your deliverables.

Now from oracle perspective:

If you work on complex queries, run your queries and check at least thrice on different environments( where you have multiple data stored) that I am not missing any join which is leading to cartesian product.

2) check that you table doesnt contain any NULL record in the column being used in where condition because we dont always use this check ( column is not NULL)