How to replace value in fstab file?

Shell Programming and Scripting
1

Hi,
I am looking to replace value (fifth and sixth ) column to "0 0" in /etc/fstab file by scripting.
can any one please help me.

/dev/VolGroup00/tmp /tmp ext3 defaults 1 1

2

Scripting changes to vital system files is very, very dangerous. Be sure you have a plan B in case that goes badly.

If I had to, I'd be paranoid and verify every part of the line.

awk '(NF==6)&&($1=="/dev/VolGroup00/tmp")&&($2=="/tmp")&&($3=="ext3")&&($4=="defaults"){ print $1,$2,$3,$4,1,1; next } 1' /etc/fstab > /tmp/fstab
# Uncomment once you've tested and are sure /tmp/fstab is what you want it to be.
# use cat, not mv, because mv may change permissions and ownership
# cat /tmp/fstab > /etc/fstab
rm -f /tmp/fstab
3

May be add few steps like take a backup of file. and validate file.

First to make backup

[ ! -d "/root/fstab_backup" ] && mkdir /root/fstab_backup
cat /etc/fstab > /root/fstab_backup/fstab.${date +%j_%y}.BACKUP

Now to test it

mount -fav

Just make sure to check man pages on system to validate. Also run each command by itself and validate.