sudo mount -o loop Sample.iso /tmp/mnt
cd /tmp/mnt
tar-cvf /tmp/sample.tar *
sudo umount /tmp/mnt

#!/bin/bash
sudo mount -o loop Sample.iso /tmp/mnt
cd /tmp/mnt
tar -cvf /tmp/sample.tar *
#Got to the old working directory. **NOTE**: OLDPWD is set automatically.
cd $OLDPWD
#Now we're able to unmount it.
sudo umount /tmp/mnt

sudo mount -o loop Sample.iso /tmp/mnt
cd /tmp/mnt
tar -cvf /tmp/sample.tar *
sudo umount /tmp/mnt

sudo mount -o loop Sample.iso /tmp/mnt
( cd /tmp/mnt && tar -cvf /tmp/sample.tar * )
sudo umount /tmp/mnt

( cd dir && somecommand )