In case that you need hash key existance (and not only) check use exists.

my %filesystems = (
   hosta => { desc => 'x', filesystemA =>  qq|/the/first/filesystem|, 
+filesystemB => qq|/the/second/fielsystem| },
   hostb => { desc => 'r', filesystemA => qq|/the/first/filesystem|, f
+ilesystemB => qq|no filesystemB for 2nd host|}
);


print "filesystemA exists\n" 
  if exists $filesystems{'hosta'}->{'filesystemA'};

print "no_such_fs does not exist\n" 
  if not exists $filesystems{'hosta'}->{'no_such_fs'};

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In reply to Re^3: Mulitple values for a key in a hash by sh1tn
in thread Mulitple values for a key in a hash by wishartz

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