what is the most efficient regex (vim/perl) to replace 100 'a' characters with 300 'b' characters. I can get the search part correct :%s/a\{100}/?????? but the 'replace' portion eludes me.

1 Answer 1


This can be done with :%s/a\{100}/\=repeat('b',100)/

  • that does it. i'd been using the search form in the replace portion and just did not work. i don't know how to mark this as the correct answer, but it does exactly what i was looking for. thanks. Commented Nov 22, 2018 at 1:19
  • @iohannfust click the greyed-out check mark next to the answer to mark it as “accepted”
    – D. Ben Knoble
    Commented Nov 22, 2018 at 3:06

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