Not even close: 

$ seq 20 | perl -pe's/$/,/ if not$.%5'
1
2
3
4
5,
6
7
8
9
10,
11
12
13
14
15,
16
17
18
19
20,

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In reply to Re^2: Concatenate every 5 lines of input with a comma. by jwkrahn
in thread Concatenate every 5 lines of input with a comma. by jsh

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