You can use the fsck subcommand to check for problems in your data. What
can be checked depends on the key-value [[backend|backends]] you've used
for the data. For example, when you use the SHA1 backend, fsck will verify
that the checksums of your files are good. Fsck also checks that the
[[numcopies|copies]] setting is satisfied for all files.

	# git annex fsck
	fsck some_file (checksum...) ok
	fsck my_cool_big_file (checksum...) ok
	...

You can also specify the files to check.  This is particularly useful if 
you're using sha1 and don't want to spend a long time checksumming everything.

	# git annex fsck my_cool_big_file
	fsck my_cool_big_file (checksum...) ok