Re: OT help with midi2ly on command line mac os blind user

[David Wright]

On Mon 14 Mar 2016 at 22:16:28 (-0500), Daniel Contreras wrote:
>    Hello all, 
>    I am trying to wrap my head around this whole command line terminal. I am
>    attempting to follow the steps that are listed on the �Mac OS� section on
>    the lilypond website. I ,think, I have followed each step correctly
>    through step 4, which is to make the file executable. I am confused as to
>    what step 5 is talking about. It is the following: 
> 
>     1. Now, add this directory to your path. Modify (or create) a file
>        called .profile in your home directory such that it contains
> 
>  export PATH=$PATH:~/bin
> 
>        This file should end with a blank line. 
>        I guess my questions are the following: 
>        How will these steps help me in using midi2ly?

Starting at step 5 (called 1 in your quote above), when your bash
shell starts up as a login shell, it reads your ~/.profile file for
your personal initialisation.

(But only a login shell, so that these commands are not repeated every
time a subsequent shell starts.)

Users who write scripts and/or programs that they want to invoke just
by typing their name will typically place these scripts (or links to
them) in one directory conventionallly called ~/bin and step 1 of the
instructions shows you how to make that if it isn't already there.

(You can run scripts/programs from anywhere by giving a pathname,
ie something containing a /, but they must be in your $PATH if you
just want to be able to type a bare name without a slash.)

Steps 2 and 3 show how you can write scripts that you will execute
by typing their (short) name, which will in turn execute a program
that has a very long name. "$@" will pass on to that program any
options and arguments you give.

For you to be able to invoke a program in this way, your script must
be executable, and that's step 4. (You need to do it to each script.)
You will then be able to type, eg, midi2ly -h   or midi2ly --version
and bash will run that script, see that it starts with #!/bin/bash
and start a bash subshell which will execute the exec command on the
appropriate program.

So the final link in the chain is to put your ~/bin into your $PATH.
~/.profile does this with   export PATH=$PATH:~/bin

When this is executed in your ~/.profile, the righthandside is
expanded by the shell into

the-whole:of-the:preexisting:value-of-$PATH-in:a-list:~/bin

where you'll see lots of directories separated by : (colons) with
yours tacked onto the end. This string then becomes the new value of
$PATH. "export" is necessary to make bash pass it to all subsequent
commands and subshells.

>        Also, can anyone give me an example of what to type in the terminal to
>        convert a midi file to lilypond format? 

midi2ly name-of-midi-file.midi

On my system, it creates (or will overwrite without warning) a file in
the current directory called   name-of-midi-file-midi.ly   unless I
specify -o newfilename.

Cheers,
David.