Re^2: perl -d: puzzling behavior when run in program in current directory

[jkeenan1]

When I create a new directory at the same level (~/learn/perl/oldp5p), then copy over all the contents from the original directory to the new one, then run the program from the new directory, the problem appears:

$ cd ../oldp5p
$ cat abc.pl
print "hello world\n";
print "goodbye world\n";
$ perl abc.pl
hello world
goodbye world
$ perl -d abc.pl
hello world
goodbye world
Var=

But when I wipeout the original directory, create a new directory with the same name, then copy over the test program to the new directory and run the debugger, the problem goes away.

$ cd ..
$ rmtree1.pl p5p
$ mkdir p5p
$ cp -v oldp5p/abc.pl p5p
'oldp5p/abc.pl' -> 'p5p/abc.pl'
$ cd p5p
$ perl abc.pl
hello world
goodbye world
$ perl -d abc.pl

Loading DB routines from perl5db.pl version 1.49_04
Editor support available.

Enter h or 'h h' for help, or 'man perldebug' for more help.

main::(abc.pl:1):    print "hello world\n";
  DB<1> q

So if seems as if something in the original directory is "polluting" the operation of the debugger.

[jkeenan1]

Aha! Here is the explanation.

Two days ago I was working on this bug report: RT 130445. In the course of that work, I created this hidden file in the original directory:

$ ack 'db\.out' .
.perldb
1:&parse_options("NonStop=0 TTY=db.out");

So when I ran the perl debugger over any program from that directory, it was silently processing '.perldb' and setting the 'NonStop' option and redirecting legitimate output to a file in that directory called 'db.out'.

Once I deleted '.perldb', the output of perl -d abc.pl returned to normal.

Thank you very much.

[Anonymous Monk]

So if seems as if something in the original directory is "polluting" the operation of the debugger.

Just some ideas: .dot files, hard links, symbolic links, directory permissions, ACLs? Does ls -lAR on the respective directories show anything like that?