$ cat index_DATA
1   32
4   19
28  39
34  123
321 321
324 329
325 349
340 509
$ perl -nle's/(\d*)(\d*)\s+\1(\d*)/$1$2-$3/;s/-$//;print' index_DATA
1-32
4-19
28-39
34-123
321
324-9
325-49
340-509
$

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perl -e"map print(chr(hex(( q{6f634070617a6d692e7273650a}=~/../g)[hex]))), (q{375542349abb99098106c}=~/./g)"

In reply to Re: eliding number ranges by pizza_milkshake
in thread eliding number ranges by qq

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