Why is the $_ variable of the outer foreach() loop getting clobbered by the inner while() loop in the code, below? 
      1 #! /usr/bin/perl -w
      2
      3 my @test_files = glob "*.txt";
      4
      5 foreach (@test_files) {
      6   print "Starting processing of file, $_.\n";
      7   open TEST_FILE, "< $_" or die "Couldn't open test file, '${_
+}', for reading: ($!)";
      8
      9   while (<TEST_FILE>) {
     10     print;
     11   }
     12
     13   print "Ending processing of file, $_.\n";
     14 }

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When I run the code, above, I get this output: (The local directory contains 2 *.txt files: test1.txt and test2.txt.) 
Starting processing of file, test1.txt.
Line 1 from 'test1.txt'
Line 2 from 'test1.txt'
Line 3 from 'test1.txt'
Use of uninitialized value in concatenation (.) or string at ./test.pl
+ line 13, <TEST_FILE> line 3.
Ending processing of file, .
Starting processing of file, test2.txt.
Line 1 from 'test2.txt'
Line 2 from 'test2.txt'
Line 3 from 'test2.txt'
Use of uninitialized value in concatenation (.) or string at ./test.pl
+ line 13, <TEST_FILE> line 6.
Ending processing of file, .

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Note the missing filenames at the ends of both "Ending processing..." lines, as well as the warnings immediately preceeding them. Here are the contents of "test1.txt" and "test2.txt":
test1.txt: 
Line 1 from 'test1.txt'
Line 2 from 'test1.txt'
Line 3 from 'test1.txt'

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test2.txt: 
Line 1 from 'test2.txt'
Line 2 from 'test2.txt'
Line 3 from 'test2.txt'

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Thanks!

In reply to $_ getting clobbered by inner loop. by dbanas

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