Dear all,
Please find my file system details.I would like to remove the old file(main target is increase the space,right now 76 % current space).Kindly give the advice to increase the space.

Filesystem Size Used Avail Use% Mounted on
15G 6.4G 7.2G 47% /
124G 89G 29G 76% /opt
/dev/sda1 190M 18M 163M 10% /boot