awkで最後の列からn個前の列を抽出する場合は、以下のようにすればよい。
awk '{print $(NF-n)}'
[root@BS-PUB-CENT7-01 ~]# cat /tmp/test.txt
aaa="1" bbb="2" ccc="3" ddd="4"
aaa="11" bbb="21" ccc="31" ddd="41"
aaa="12" bbb="22" ccc="32" bbb="3rqt" ddd="42"
aaa="13" bbb="23" ccc="33" ddd="43"
aaa="14" bbb="24" ccc="34" ddd="44"
aaa="15" bbb="25" ccc="35" ddd="45"
aaa="16" bbb="26" ccc="36" ddd="46"
aaa="17" bbb="27" ccc="37" ddd="47"
aaa="18" bbb="28" ccc="38" ddd="48"
[root@BS-PUB-CENT7-01 ~]# awk '{print $(NF-1)}' /tmp/test.txt
ccc="3"
ccc="31"
bbb="3rqt"
ccc="33"
ccc="34"
ccc="35"
ccc="36"
ccc="37"
ccc="38"
[root@BS-PUB-CENT7-01 ~]# awk '{print $(NF-2)}' /tmp/test.txt
bbb="2"
bbb="21"
ccc="32"
bbb="23"
bbb="24"
bbb="25"
bbb="26"
bbb="27"
bbb="28"
