awk的gsub替换没有替换上

文本内容如下my-friends：
Hans Jurgen School
Unter den Linden 78
D-10117 Berlin
Germany

#SORTKEY: Jones, Adrian
Adrian Jones
371 Montgomery Park Road
Henley-on-Thames RG9 4AJ
UK

#SORTKEY: Brown, Kim
Kim Brown
1841 S Main Street
Westchester, NY 10502
USA
现在用awk执行两次替换
cat my-friends |
   awk -v RS="" '{gsub("\n","^Z");print}' |
        awk -v ORS="\n\n" '{gsub("^Z","\n");print}'
输出结果：
#SORTKEY: School, Hans Jurgen^ZHans Jurgen School^ZUnter den Linden 78^ZD-10117 Berlin^ZGermany

#SORTKEY: Jones, Adrian^ZAdrian Jones^Z371 Montgomery Park Road^ZHenley-on-Thames RG9 4AJ^ZUK

#SORTKEY: Brown, Kim^ZKim Brown^Z1841 S Main Street^ZWestchester, NY 10502^ZUSA
为何^Z没被替换掉啊？？？？？？
运行平台：Linux version 2.6.18-164.el5 (mockbuild@x86-002.build.bos.redhat-com) (gcc version 4.1.2 20080704 (Red Hat 4.1.2-46)) #1 SMP Tue Aug 18 15:51:54 EDT 2009

cat my-friends |awk -v RS="" '{gsub("\n","^Z");print}' |awk -v ORS="\n\n" '{gsub("\\^Z","\n");print}'