I have some unused space on my disk, and decided to use a little of it to create a separate /var partition.  There might be an easier way to do this, but my idea is to copy the existing /var directory to the partition;mount the partition over the existing /var directory;using another system, either another distro on the disk or a liveCD, to delete the original /var contents while the partition is notmounted.I've done the first 2 steps, and it seems OK so far.  I've made an entry in fstab to mount on boot, which I'll test before deleting.  But I'm wondering if this is a valid strategy, and also if it's a good idea and/or if there is a better way.  It's somewhat of a learning experience for me to play around more with mounting beyond the basics.Edit (results):Thanks to the suggestions below, I completed step 3 without the need to use a 2nd system.  The method I used was to remount the root fs using the command mount --bind / /mnt/temp, then going to /mnt/temp/var and deleting the files and directories there.The one suggestion made after I did it was to create a dummy file, and then check the mounted /var directory to confirm that it was not seen in that directory.  But I compared timestamps to see that they were different, so I felt confident that I was OK.Thanks for the suggestions, everyone.
mounting to non-empty directory, then later deleting original files
filesystems;mount;administration
If you're on Linux you can :Mount your root filesystem on a random mountpoint. I usually use /mnt for this sort of things.mount --bind / /mntThen you can (re)move the files from /mnt/varNot all OS's allow a filesystem mounted on a second mount point at the same time, that's why I wrote 'on Linux'. Just try the mount, it won't break anything.