Ghostscript installed but not found RGhost::Config::GS[:path]='/path/to/my/gs' - ruby-on-rails

Question

I've been trying for a few hours now solve this problem and I looked everywhere for a solution and I did not find one. I'm trying to run a spec test for my project and I have the following error coming up:
RuntimeError:
Ghostscript not found in your system environment (linux-gnu).
Install it and set the variable RGhost::Config::GS[:path] with the executable.
Example: RGhost::Config::GS[:path]='/path/to/my/gs' #unix-style
RGhost::Config::GS[:path]="C:\\gs\\bin\\gswin32c.exe" #windows-style
And I do try to put RGhost::Config::GS[:path]='/usr/local/bin/gs' and it returns:
bash: RGhost::Config::GS[:path]=/usr/local/bin/gs: No such file or directory
but ghostscript is installed, I did everything (make, sudo make install, etc etc) and when I run gs -v it returns:
GPL Ghostscript 9.26 (2018-11-20)
Copyright (C) 2018 Artifex Software, Inc. All rights reserved.
When I use the user interface and search for "gs" in the "Files" application, it is found in /home/marcelle/projects/ghostscript-9.26/bin/gs and I also tried:
RGhost::Config::GS[:path]='/home/marcelle/projects/ghostscript-9.26/bin/gs'
and it returns the same error:
bash: RGhost::Config::GS[:path]=/home/marcelle/projects/ghostscript-9.26/bin/gs: No such file or directory
I also tried to delete ghostscript from my notebook with autoremove and purge and installed it again using what I mentioned before (./configure, make, sudo make install), restarted the notebook, the terminal and nothing.
PS: I'm using Ubuntu 20.04.

Answer 1

I managed to figure out a solution. Looking for the code for the Rghost, what I saw in its spec is that the path expected was different than the path the ghostscript really is.
When I run whereis or which on my terminal, it returns:
which gs
/usr/local/bin/gs
So I was trying to point to this path. But seeing the spec test for Rghost which I found on github for Rghost, we can see that it expects /usr/bin/gs:
it 'should detect linux env properly' do
RbConfig::CONFIG.should_receive(:[]).twice.with('host_os').and_return('linux')
File.should_receive(:exists?).with('/usr/bin/gs').and_return(true)
RGhost::Config.config_platform
RGhost::Config::GS[:path].should == '/usr/bin/gs'
end
So it expects /usr/bin and not /usr/local/bin.
Then I just copied to that path and the spec ran with no problems anymore:
sudo cp /usr/local/bin/gs /usr/bin

Answer 2

I've no experience with Ruby at all, but I also got this error when using asciidoctor, which uses rghost for the PDF generation.
The command RGhost::Config::GS[:path]='/path/to/my/gs' mentioned in the error is not a shell command, which is why bash couldn't handle it. However, to me it wasn't immediately clear what to do with this command either. I expected an easy way to set this variable somewhere, but couldn't find it.
What worked for me was searching the rghost.rb file, which is where this variable is set and can be changed. In Windows, it was located in C:\Ruby30-x64\lib\ruby\gems\3.0.0\gems\rghost-0.9.7\lib\rghost.rb.
In this file, I added the following line, which solved the problem:
RGhost::Config::GS[:path]="C:\\Program Files\\gs\\gs9.55.0\\bin\\gswin64c.exe"
NB: the mentioned paths can be different for everyone, so make sure to use that paths that are valid for your system.