On 3/27/2012 1:31 PM, Ted Ts'o wrote:
On Tue, Mar 27, 2012 at 01:26:14PM -0400, Michael Conrad wrote:
I would request that either the order of fields become stable by
printing empty lines for missing fields (and documented), or the "-o
value" be done away with, since I can't see any reason anyone would
want random output in a script-friendly format, and the fact that it
exists is likely to lead people astray.
Try using this way, which was its intended usage:
blkid -o value -s TYPE -t UUID=a3dc6f56-da22-4079-bf75-1fa2ce1aa4b0
(replace part following -t with the search criteria you want; for
example, "-t LABEL=backup").
It was intended to be used a script-friendly way, and I believe there
are shell scripts using in this fashion. So please don't change blkid
-o value.
I see how that could be useful if and only if you use exactly one "-s",
but if you requested more than one "-s" they still come out in
non-stable order. It's like running a SQL query and having all the
columns shifted because the first one was a NULL. If you're on a system
where all the volumes have labels, types, and uuids (and nothing else)
it's very misleading.
At the very least, I would appreciate it if the man page mentioned that
"-o value" should only ever be used with exactly one "-s".
-Mike
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