classes *DBM has a method #invert, but this method don't seem to work or
 I've not understood how to use it :

pigeon% cat b.rb
#!/usr/bin/ruby
require "gdbm"
dbm = GDBM.open("toto")
dbm["a"] = "1"
dbm["b"] = "2"
dbm.each { |x, y| print "#{x}--#{y}\n" }
mbd = dbm.invert
mbd.each { |x, y| print "#{x}--#{y}\n" }
dbm.close
pigeon% b.rb
a--1
b--2
a--1
b--2
pigeon% 


Guy Decoux