This probably doesn't help, but your regex works for me when I run it. Can you give more details as to how it's failing for you? 
$line = "this is a test [[ this is a test ]
]";
$line =~ s/\[\[[^\]]*\]\s*\]/***FOO***/sg;
print "Line: '$line'\n";

[download]
prints 
Line: 'this is a test ***FOO***'

[download]
You also don't need the /m modifier in this case, since you're not using ^ or $ in your regex.

In reply to Re: substition in multiple lines by thelenm
in thread substition in multiple lines by yangtse

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