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in reply to dir match, dir may or may not appear

What syntax error and where? Perl is usually quite informative with its error messages.

Most likely, it's a syntax error in your regular expression. See perlre, especially about quantifiers.

Personally, I would reformulate the problem as "any directory that starts with /usr/ and ends with /bin, and do the checking in two regular expressions instead.

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Re^2: dir match, dir may or may not appear
by hellosarathy (Novice) on Jan 12, 2016 at 09:13 UTC
    the regexp has errors: 
    Nested quantifiers in regex  marked by <-- HERE in m/^/usr/(/[^/]+{ <-
+- HERE 0,1})/bin//

    [download]
    Two expressions is fine,is there a one liner, as this could increase in future...?
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[d/l]

      Yes, see perlre. If one expression is too difficult, why not use two?

      If you really need to write it in one expression, use a group and quantify that:

      m!^/usr(?:/[^/]+)?/bin!;

      [download]
[reply]
[d/l]

      a quantifier is +

      a quantifier is {0,1}

      You can't have {0,1}{0,1}{0,1}{0,1}

      You can't have +{0,1}+{0,1}

      If you want a pattern ([^/]+) to repeat, you have to group it

      perlre, perlretut, perlrequick describe these words I've used, go fish

[reply]
[d/l]

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