/m changes where ^ and $ can match; /s changes what . can match. Since you don't have any of ^, $, or . in your regex, the flags do nothing.

The problem is that you have a regex that only matches multiple lines, but you are trying to match each line of the file against it individually, and of course none of them do match.

In reply to Re^3: multiline regex: heredoc vs. reading file by ysth
in thread multiline regex: heredoc vs. reading file by bowei_99

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