Perl problems

James Wilkinson ubuntu at
Thu May 12 16:41:10 UTC 2005

Stephen R Laniel wrote:
> The problem is that by
> default -- and unintuitively, I think -- bash doesn't look
> in the current directory for executable commands. There's
> probably a good reason for it, but it differs from, for
> instance, the MS-DOS shell's behavior.

Well, MS-DOS isn't a multi-user operating system. Basically, under
MS-DOS, everything is trusted, everything is allowed (or plain

Unix is designed for situations where one user (which might or might not
be root) can investigate a directory whose contents have been controlled
by an untrusted user.

Imagine a university systems administrator, with a box that has shell
access available to students, and a new student whose principal
interests are warez, cracking, porn, and a *really* fast internet
connection [1].

Imagine the sysadmin investigating some processes that seem to be
racking up a lot of CPU time, network traffic, and "temporary" files in
/var/tmp. And wanting to look in the student's home directory.

Or imagine her investigating the ftp upload directory.

She does *not* want to try running any of those files unless she
explicitly requests it. (And, if she has any sense, she will only try
running anything on a honeynet box [2] or something completely


[1] It took me ten years to get the Internet speeds outside university
that I had when I arrived at university. 

[2] Honeytrap, honeynet: systems or networks that are kept well away
from "real" networks, designed to attract crackers and other low-life
and allow observation in something like their natural environment.

Results may well be passed to the police.

E-mail address: james | "My aunt's camel has fallen in the mirage."  |     -- "Soul Music", Terry Pratchett.

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