LVM: Decrease/shrink size of a physical volume by deallocating free space from removed logical volume

I have the following LVM partition: # df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/data-root 5.3G 4.2G 864M 84% / ... /dev/mapper/data-install 6.8G 5.7G 783M 89% /install # vgs VG #PV #LV #SN Attr VSize VFree data 1 2 0 wz--n- `. Also I would like to accomplish this using the command line alone (no GUI). It is also worth noting that the root/system logical volume is active and in use at all times.