More (or less) Tommies

[Mark Rogers]

On 16 October 2014 18:28, roadcone <roadcone at gmx.com> wrote:
> I see from your comments that Linux won't first
> search the current directory. And, of course, if I use ./ then the
> downloaded copy of get_iplayer runs - just like magic.

This is, of-course, quite an important security feature.

The directory you're currently in (probably your home directory) is
usually writeable by your user. So it's not inconceivable that
something could drop an executable file into that directory that
deleted all your data and call it "ls", so that if you ran "ls" from
there it caused havoc. But it won't, because when you run it it won't
look there unless you tell it to, and if you instead run ./ls then
it's fair to assume that's what you meant to do.

It's this attitude to security over convenience that crops up a lot
when you move from Windows to Linux, and I mention it only because the
inconvenience is generally more noticeable than the benefits! (It's
quite possible to add "." to the path to defeat this, but you
shouldn't for this reason.)

A related note is that it won't run unless it's marked as executable.
If the program you downloaded is inside an archive then that's
probably been set for you, but it's not inconceivable that this won't
also cause a problem for you one day.

To check permissions, use:
    ls -l get_iplayer
.. and if the "x" bits are missing, set them
    chmod +x get_iplayer

That's obviously not an issue here as it's working, just one to
remember for future.

Mark
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