What is the /~ file on Mac OS X? In the root directory of my Mac (10.10.4) I see a file named just ~ (tilde):

$ ls -l /~
-rw-------  2 root  wheel  2187264 Mar 23 22:33 /~


file just reports it as "data". For reference, here are the first 256 bytes as seen through xxd:

0000000: d0fa d0da 0010 0000 2800 0000 9002 0000  ........(.......
0000010: 1b00 0000 0000 0000 0c00 0000 2c00 0000  ............,...
0000020: ca02 0000 0000 0000 0e00 0000 0000 0000  ................
0000030: 3c63 6174 616c 6f67 3e00 0000 0b00 0000  &lt;catalog&gt;.......
0000040: 0010 0000 5374 7269 6e67 0000 0a00 0000  ....String......
0000050: 0010 0400 4172 7261 7900 0000 0b00 0000  ....Array.......
0000060: 0090 0500 4275 6e64 6c65 0000 0a00 0000  ....Bundle......
0000070: 0010 0700 436c 6169 6d00 0000 0c00 0000  ....Claim.......
0000080: 0090 0800 5365 7276 6963 6500 0900 0000  ....Service.....
0000090: 00a0 0800 5479 7065 0000 0000 0f00 0000  ....Type........
00000a0: 00a0 0900 5554 4942 696e 6469 6e67 0000  ....UTIBinding..
00000b0: 1500 0000 0020 0a00 4578 7465 6e73 696f  ..... ..Extensio
00000c0: 6e42 696e 6469 6e67 0000 0000 1200 0000  nBinding........
00000d0: 00a0 0a00 4f53 5479 7065 4269 6e64 696e  ....OSTypeBindin
00000e0: 6700 0000 1000 0000 00e0 0a00 4d49 4d45  g...........MIME
00000f0: 4269 6e64 696e 6700 1800 0000 0000 0b00  Binding.........


It appears to be full of file paths and extensions, along with a lot more filesystem data. Is this a standard file to have on OS X, and if so what is its purpose? If it's not a standard file, any ideas of what created it?
It is an unnecessary file. You can simply delete it if no process is currently using it. This question was already answered here.