You are running perl -p which by default processes each line in isolation, therefore your regex will never match because you don't have a line with both an opening and closing brace on it, for example.

You could change the line-ender to null to switch this behaviour off:

$ perl -lp0e 's/A\s*\{.+?\}//s' <<EOX
> A {
>   B 123
>   C xyz
> }
> EOX

[download]

This gives the empty output as you initially expected.

Update: See the discussion in the follow-up question Oneliner replace in-place adds extra spaces at the end of the file particularly in regards to the use of -l and how the order of these options is important.

🦛

In reply to Re: Why dot does not match newline in oneliner but it does in script, with /s modifier? by hippo
in thread Why dot does not match newline in oneliner but it does in script, with /s modifier? by bliako

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.