Re: Beginner in Mac OS X, and ADA and gtkAda: $prefix, and what bin, and home is usr/bob or OSX Users/bob

[Dennis Lee Bieber <wlfraed@ix.netcom.com>]

On Mon, 11 Sep 2017 16:17:51 -0700 (PDT), Mace Ayres <mace.ayres@gmail.com>
declaimed the following:

>Sorry for some beginner's questions, but.
>
>New to Mac OSX. Various software instructions may say home directory; is that OS X  ./USERS/Me
>or Unix's /usr/me:
>
>Sometime they refer to the bin directory. Which bin?
>
>Some instructions say $prefix .. what prefix is that?
>
>Is this even an understandable question?

	None of these questions are applicable to Ada itself -- they are all
dependent upon the operating system in use, so the answer is really in the
OS documentation or guide books.

	However...

Linux (UNIX) home directory is normally
		/home/{username}
and often accessible using ~

wulfraed@stretch:~$ cd ~
wulfraed@stretch:~$ pwd
/home/wulfraed
wulfraed@stretch:~$ 

	I do not know how Mac handles paths. In Linux, a leading "./" indicates
current directory (and is often used when one is trying to run a local
executable that is NOT in the search path: ./program or ./scriptfile -- for
safety, Linux will not run programs in the current directory by name only,
to avoid trojans; if someone had stuffed a virus program called, say, gcc
in your home directory, and you try to compile something by typing "gcc -o
myprog myprog.c" it will ignore the virus file and use the system gcc --
but "./gcc -o myprog myprog.c" would run the virus file )

/usr is NOT a home directory! It is a location where non-OS applications
tend to be installed...

	Normally, "bin" is likely the one at the root level of the file system
(root is a simple /): 

wulfraed@stretch:~$ ls /
bin   home            lib32       media  root  sys  vmlinuz
boot  initrd.img      lib64       mnt    run   tmp  vmlinuz.old
dev   initrd.img.old  libx32      opt    sbin  usr
etc   lib             lost+found  proc   srv   var
wulfraed@stretch:~$ 

... however, you will also find a bin under /usr

wulfraed@stretch:~$ ls /usr
bin  games  include  lib  lib32  libx32  local  sbin  share  src
wulfraed@stretch:~$ 

(sbin tends to be for privileged applications -- stuff that affects how the
system itself operates and may need root privileges to execute)

	"$prefix"		means the value of the environment variable "prefix"

wulfraed@stretch:~$ echo $PATH
/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games
wulfraed@stretch:~$ 

(I don't have a "prefix" variable defined, so I used the command search
path)
-- 
	Wulfraed                 Dennis Lee Bieber         AF6VN
    wlfraed@ix.netcom.com    HTTP://wlfraed.home.netcom.com/