It's a quick and easy command line solution, although it (like all command-line scripts) could get a little bit ugly because of having to escape some characters for the shell (this is for unix):

perl -l -n -e "/address=(.*)/ and print \$1;" yourfile.txt > emails.tx
+t
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If your example is really as simple as it appears, a simple expression like address=(.*) should do the trick. You could be more paranoid and make it

/\s*address=(.*)/
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which would only match lines that started with "address", not counting spaces, tabs, etc. You could also play around with using the @ sign. It all depends on exactly what your data looks like as to how complicated the regular expression could possibly get, but the above will probably catch most things.