[Lazarus] Building and starting Lazarus on Raspberry Pi2 with Raspbian Jessie

[Mark Morgan Lloyd]

Bo Berglund wrote:
> On Fri, 16 Oct 2015 08:57:45 +0000, Mark Morgan Lloyd
> <markMLl.lazarus at telemetry.co.uk> wrote:
> 
>> There isn't one. Even considering "standard packages", different Linux 
>> distreaux and other unix implementations (Solaris etc.) have different 
>> conventions for where they install non-core stuff: /usr/local, /opt, 
>> /opt/local and so on.
>>
>> /In/ /general/, you can rely on /usr/local/bin being on your path, or 
>> it's safe to add it. So basically, you can install both FPC and Lazarus 
>> wherever you want, and put symlinks in /usr/local/bin for the programs 
>> you need most.
>>
> 
> Thank you so much!
> This last item clarified a lot of what has been going on in my RPi....

We're wandering away from Lazarus towards more general areas, but 
craving the list managers' indulgence for a few moments...

Hint: when you're setting up a symlink, the order of the parameters is 
as though you're doing a copy.

So a copy is like this:

$ cp actual_file copy_of_file

a hard link is like this:

$ ln actual_file hard_link

and a symlink (symbolic link) is ordered the same:

$ ln -s actual_file symbolic_link

Most operations on symbolic_link are now transparently redirected to 
actual_file. I know for a fact that I am not the only person who gets 
the order wrong on occasion, and I'd also add that you need to be 
careful with relative vs absolute paths: if in doubt do something like

$ ln -s /usr/local/share/lazarus-trunk/lazarus /usr/local/bin/lazarus

rather than trying to cut corners.

> I went into the/usr/local/bin directory and made a ls -la to see what
> if any symlinks are there. Surprise! I found several dead symlinks:
..
> All of these are pointing to the erroneous root installation I did as
> root! They were probably put there my the make install command I
> issued as part of the tutorial but did not do manually after getting
> lazarus into the Pi home dir.....

But also see warnings above. BTDT.

> But them being here explains how the Jessie start menu got screwed up
> as well, because in the menu definitions were only things like
> "startlazarus %f" without any path specifier at all.

Note also that whatever desktop software you're running (OpenBox, LXDE 
etc.) will expand that %f to a filename, if given one as a parameter. 
This isn't well documented, but is completely distinct from any shell 
(environment) variables being expanded.

> One can just change the symlink and keep everythying else like the
> Menu entries....

That's right, but as I said you can also go via a (shell) script if you 
need something fancier.

-- 
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk

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