Bash Script disk partition using fdisk command

I have done new partition creation and mount the disk with manual interaction one after another, i got worked for me. But instead of doing manually i am planning to write the bash script to do all the changes for us without manual interaction.

I found the below script from internet, but i am not understand how the default option will behave using below sed command

# to create the partitions programatically (rather than manually)
# we're going to simulate the manual input to fdisk
# The sed script strips off all the comments so that we can
# document what we're doing in-line with the actual commands
# Note that a blank line (commented as "defualt" will send a empty
# line terminated with a newline to take the fdisk default.
sed -e 's/\s*\([\+0-9a-zA-Z]*\).*/\1/' << EOF | fdisk ${TGTDEV} o # clear the in memory partition table n # new partition p # primary partition 1 # partition number 1 # default - start at beginning of disk +100M # 100 MB boot parttion n # new partition p # primary partition 2 # partion number 2 # default, start immediately after preceding partition # default, extend partition to end of disk a # make a partition bootable 1 # bootable partition is partition 1 -- /dev/sda1 p # print the in-memory partition table w # write the partition table q # and we're done
EOF
sudo fdisk /dev/sdc
p
n
1
p
w
lsblk
sudo mkfs -t ext4 /dev/sdc1

But after entering option p,n,1, i wanna make default for the rest of activity then finally i need write using option w.

Can you please some one help me how to make it work

code for sfdisk

 echo ';' | sfdisk /dev/sdc mkfs.ext4 /dev/sdc1 mount /dev/sdc1 /opt/app/ uid=`blkid | grep sdc1 | sed -n 's/.*UUID=\"\([^\"]*\)\".*/\1/p'` echo "UUID=$uid /opt/app ext4 defaults 0 2" >> /etc/fstab

After executing sfdisk command after rebooting by REHL7 system not coming up back normal mode.

1 Answer

You can do this concept via regular fdisk this way:

fdisk /dev/sdb << EOF
p
n
1
p
w
EOF

You merely need to know how many default values are needed. You can have more, without any major consequences (cosmetic ones will occur, however)

n has a max of 4 options [number, first, last, remove_old_fstype]

so you'd add ( 4 - len(args) ) newlines, then proceed.

PS n doesn't need 1 as the default argument ( as 1 is a default argument ), but the method I described above should work