perl-rename 's/b(\d{2}A)/\1/' * finds and renames every part of any file with

  1. "b" followed by

  2. 2 digits followed by

  3. "A"

Is there an option or way to make the regular expression case-insensitive, i.e. also matches either an uppercase "B" for the first part and/or a lowercase "a" for the last part?

  • 1
    Can you provide some samples? its not clear what you mean by "an uppercase "A" for the first part and/or a lowercase "a" for the last part?"
    – Inian
    Commented May 2, 2020 at 10:30
  • Is [aA] what you're looking for?
    – Kusalananda
    Commented May 2, 2020 at 10:32
  • @Kusalananda Yes. The matching works then. If you provide your comment as an answer, I can mark it as solved.
    – henry
    Commented May 2, 2020 at 10:37
  • @Inian I made a mistake with the "uppercase "A"". It should have been "B" instead. I genuinely thought the enumerated list was self-explanatory.
    – henry
    Commented May 2, 2020 at 10:38

2 Answers 2


The s/// substitution command in Perl (and thus in the Perl rename command) has a flag /i to do case insensitive match. All you need to do is

perl-rename -n 's/b(\d{2}A)/\1/i' *.jpg

Remove the -n flag when you identify the files are renamed as expected. It only does a dry-run to show how the files will be eventually renamed.

To selectively allow case insensitive matching of one or several characters, use e.g. [aA] (will match either a or A).


While the /i modifier is the most common and well-known answer, it should also be said that this can be modified inside the regex itself.


This can be useful for dynamically generated patterns, patterns saved in files, etc. Also, it can be "turned off" either by limiting it to a group (capturing or otherwise):

/(?:(?i)b(\d{2}A)) Foo Bar/ # the Foo Bar portion is still case-sensitive

Or by the fact that it's a modal setting, so you can switch it back off with a negation:

/(?i)b(\d{2}A)(?-i) Foo Bar/ # again only Foo Bar is case sensitive
  • Also /sensitive(?i:insensitive)sensitive/ Commented Sep 28, 2022 at 16:07

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