Is the Perl can run under ksh Unix?

Also, the record is a bit difference...it look like

record1:
this is testing
my id is 2001
end:
record2:
this is testing2
my id is 2002
end:
record3:
this is testing
my id is 2002
end:
record4:
this is testing2
my id is 2002
end:

For the above, record 2 and 4 is duplicated. Because of the "id" and "testing2" is the same. if only one line is the same which is not called duplicated..

So Perl or any friend can help for the script?