# ls -ld *perm{,/A.pm}
drwx------  2 root root 17 Jul 28 15:16 badperm
-rw-------  1 root root 48 Jul 28 15:16 badperm/A.pm
drwxr-xr-x  2 root root 17 Jul 28 15:16 goodperm
-rw-r--r--  1 root root 49 Jul 28 15:16 goodperm/A.pm

# head *perm/A.pm | grep .
==> badperm/A.pm <==
package A; print "Here I am (badperm/A).\n"; 1;
==> goodperm/A.pm <==
package A; print "Here I am (goodperm/A).\n"; 1;

# perl -we 'BEGIN { @INC=qw/badperm goodperm/; } use A'
Here I am (badperm/A).

$ perl -we 'BEGIN { @INC=qw/badperm goodperm/; } use A'
Here I am (goodperm/A).

$ perl -we 'BEGIN { @INC=qw/badperm/; } use A'
Can't locate A.pm in @INC (@INC contains: badperm) at -e line 1.
BEGIN failed--compilation aborted at -e line 1.