Hide part of match from grep output

GNU grep has the -P option for perl-style regexes, and the -o option to print only what matches the pattern. These can be combined using look-around assertions (described under Extended Patterns in the perlre manpage) to remove part of the grep pattern from what is determined to have matched for the purposes of -o.

$ grep -oP 'foobar \K\w+' test.txt
bash
happy
$

The \K is the short-form (and more efficient form) of (?<=pattern) which you use as a zero-width look-behind assertion before the text you want to output. (?=pattern) can be used as a zero-width look-ahead assertion after the text you want to output.

For instance, if you wanted to match the word between foo and bar, you could use:

$ grep -oP 'foo \K\w+(?= bar)' test.txt

or (for symmetry)

$ grep -oP '(?<=foo )\w+(?= bar)' test.txt

If you want all of the numbers after UUIDs in this bucket, you can use sed like so:

$ zcat file.gz | sed -n 's/^.*UUIDs in this bucket //p' 
8501792126581991569,8073766106536916628,4830289023695906800,6135982080116553120,8306484440313978157,9040948912536460872,8471856544054164043,5431263453539111247,7661719762428556576
6501792126581991569,8073766106536916628,4830289023695906800,6135982080116553120,8306484440313978157,9040948912536460872,8471856544054164043,5431263453539111247,7661719762428556576

Or, use perl and output the full SQL statement:

$ zcat file.gz | perl -ne 'chomp;if(s/^.*UUIDs in this bucket //){@uuids=split(/,/); $k{$_}++ for @uuids} END{ print "insert into sometable (uuid) values (" , join ",",map{qq/"$_"/} keys(%k); print ");\n"}' 
insert into sometable (uuid) values ("6135982080116553120","4830289023695906800","8501792126581991569","9040948912536460872","7661719762428556576","8471856544054164043","8306484440313978157","6501792126581991569","5431263453539111247","8073766106536916628");

Or, slightly more legibly:

$ zcat file.gz | 
    perl -ne 'chomp;
              if(s/^.*UUIDs in this bucket //){
                @uuids=split(/,/); 
                $k{$_}++ for @uuids
              }
              END{
                print "insert into sometable (uuid) values (" , 
                           join ",",map{qq/"$_"/} @uuids; 
                print ");\n"
            }'
insert into sometable (uuid) values ("6501792126581991569","8073766106536916628","4830289023695906800","6135982080116553120","8306484440313978157","9040948912536460872","8471856544054164043","5431263453539111247","7661719762428556576");