Probably better as:

perl -sne " BEGIN { @ARGV = map glob( $_ ), @ARGV } /\[$TAG\]/ ... /\[
+\/$TAG\]/ && print qq[$ARGV($.):$_]; close ARGV if eof "  --  -TAG=ta
+th_tag  ./*/dir/*.ext
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1. glob works on strings, not arrays.
2. If /\[$TAG\]/ and /\[\/$TAG\]/ are on the same line then .. will not work correctly.
3. To get the correct line number for each file you need to close the filehandle at eof.
4. And, without the -- switch the perl interpreter will try to parse -TAG as a valid perl option.

/\[$ARGV[0]\]/  .. /\[\/$ARGV[0]\]/
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/\<$ARGV[0]\>/  .. /\<\/$ARGV[0]\>/
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Really I don't understand your reply, sure for my ignorance: i go to study the -s operator

See perlrun for -s. It cause perl to parse command line arguments of the form: -XYZ=pqr which causes the variable $xyz to have the value "pqr" within the program or one-liner.

## run perl; enable arg parsing
perl -s 

## expand filename globs
-e"BEGIN{@ARGV=glob@ARGV}" 

## if between the tags, print filename(linenumber):line
-nle"/\[$TAG\]/../\[\/$TAG\]/&& print qq[$ARGV($.):$_]" 

## Supply the tagname to search for; and the fileglob
-TAG=tath_tag ./*/dir/*.ext
[download]

(Obviously, you'll need to put that all on one line to run it.)

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