how to print the first occurence of a column matching more than once with awk

I have a log_file with all my backups and a column with value yes means it won't be deleted by the retention policy (Preserved). there could be 1 or more rows having that preserved column = yes for a specific vmname.

My input is :

=    FULL     ==   20210105   ==     2100     == ASR-FULL-20210105-2100 ==  YES  =    FULL     ==   20210202   ==     2100     == ASR-FULL-20210202-2100 ==  YES  =    FULL     ==   20210302   ==     2100     == ASR-FULL-20210302-2100 ==  YES  =    FULL     ==   20210406   ==     2100     == ASR-FULL-20210406-2100 ==  YES  =    FULL     ==   20210105   ==     2146     == DNS10_7-FULL-20210105-2146 ==  YES  =    FULL     ==   20210202   ==     2153     == DNS10_7-FULL-20210202-2153 ==  YES  =    FULL     ==   20210302   ==     2148     == DNS10_7-FULL-20210302-2148 ==  YES  =    FULL     ==   20210406   ==     2122     == DNS10_7-FULL-20210406-2122 ==  YES  =    FULL     ==   20210105   ==     2105     == execnet.0-FULL-20210105-2105 ==  YES  =    FULL     ==   20210202   ==     2106     == execnet.0-FULL-20210202-2106 ==  YES  =    FULL     ==   20210302   ==     2106     == execnet.0-FULL-20210302-2106 ==  YES  =    FULL     ==   20210406   ==     2105     == execnet.0-FULL-20210406-2105 ==  YES  =    FULL     ==   20210106   ==     0200     == Prtgadmin.0-FULL-20210106-0200 ==  YES  =    FULL     ==   20210105   ==     2216     == sandbox.0-FULL-20210105-2216 ==  YES  =    FULL     ==   20210202   ==     2227     == sandbox.0-FULL-20210202-2227 ==  YES  =    FULL     ==   20210406   ==     2152     == sandbox.0-FULL-20210406-2152 ==  YES  =    FULL     ==   20210105   ==     2236     == wwwp.0-FULL-20210105-2236 ==  YES  =    FULL     ==   20210202   ==     2249     == wwwp.0-FULL-20210202-2249 ==  YES  =    FULL     ==   20210105   ==     2259     == wwws.0-FULL-20210105-2259 ==  YES  =    FULL     ==   20210202   ==     2314     == wwws.0-FULL-20210202-2314 ==  YES  =    FULL     ==   20210105   ==     2259     == webhost.0-FULL-20210105-2259 ==  YES  

My desired output is to print the n-1 oldest matches (top n-1)

ASR-FULL-20210105-2100          ASR-FULL-20210202-2100           ASR-FULL-20210302-2100           DNS10_7-FULL-20210105-2146       DNS10_7-FULL-20210202-2153       DNS10_7-FULL-20210302-2148       execnet.0-FULL-20210105-2105    execnet.0-FULL-20210202-2106     execnet.0-FULL-20210302-2106     sandbox.0-FULL-20210105-2216     sandbox.0-FULL-20210202-2227     wwwp.0-FULL-20210105-2236       wwws.0-FULL-20210105-2259    

I can so far have the below result by running the below awk commands but It shows the most recent matches instead. I'd also like to have one awk command ideally . The year filter is not that important .

# cat bkp_list.log| grep -E '*2021.*YES'| awk -F[==-] 'cnt[$8]++{if (cnt[$8]>1) print prev=$0;next}' |awk -F[==] '{print $8}'   

ASR-FULL-20210202-2100  ASR-FULL-20210302-2100  ASR-FULL-20210406-2100  DNS10_7-FULL-20210202-2153  DNS10_7-FULL-20210302-2148  DNS10_7-FULL-20210406-2122  execnet.0-FULL-20210202-2106  execnet.0-FULL-20210302-2106  execnet.0-FULL-20210406-2105  sandbox.0-FULL-20210202-2227  sandbox.0-FULL-20210406-2152  wwwp.0-FULL-20210202-2249  wwws.0-FULL-20210202-2314  

Thank you

https://stackoverflow.com/questions/67218835/how-to-print-the-first-occurence-of-a-column-matching-more-than-once-with-awk April 23, 2021 at 02:21AM