fail.rb

# Should succeed, has TYPE=".."
GOOD_BLKID  = %{/dev/vg/root: LABEL="/" UUID="6a1e5f4f-37c9-4809-969a-89cf6725cbbd" TYPE="ext4"}
# No TYPE="ext[34]", shouldn't succeed
BAD_BLKID   = %{/dev/vg/root: LABEL="/" UUID="6a1e5f4f-37c9-4809-969a-89cf6725cbbd" TYPE="reiserfs"}
TYPE_REGEX  = /TYPE=\"(\S+)\"/
MATCH_EXT34 = /ext[34]/

# With the good blkid, this should return non-nil if it's not faulty
r = TYPE_REGEX.match(GOOD_BLKID) { |m| m =~ MATCH_EXT34 }                         # => nil
puts r.inspect
# With the bad blkid, this should return nil if it's not faulty
r = TYPE_REGEX.match(BAD_BLKID) { |m| m =~ MATCH_EXT34 }                          # => nil
puts r.inspect
# In reality, the above will both fail in a normal Ruby environment where =~
# returns nil by default, as MatchData (m.class in the above block) does not
# implement a method for it.


# Both of these should work as expected, rather.
r = TYPE_REGEX.match(GOOD_BLKID) { |m| m[1] =~ MATCH_EXT34 }                      # => 0
puts r.inspect
r = TYPE_REGEX.match(BAD_BLKID) { |m| m[1] =~ MATCH_EXT34 }                       # => nil
puts r.inspect