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Hello FreeSurfer Developers,

I found what I believe to be a bug. Typically I can load mgz files into my Matlab program without any trouble. 

But if the path containing the mgz file has a space then I get an error.

When I run this very short script in Matlab calling the MRIread function (/Applications/freesurfer/7.4.1/matlab/MRIread.m):

filepath = char("/Users/user/Documents/folder space test/data/mri.mgz");

mri = MRIread(filepath);

I get the following error:

gunzip: can't stat: /Users/user/Documents/folder (/Users/user/Documents/folder.gz): No such file or directory
gunzip: can't stat: space (space.gz): No such file or directory
gunzip: can't stat: test/data/mri.mgz (test/data/mri.mgz.gz): No such file or directory

ERROR: problem reading fname
SWITCH expression must be a scalar or a character vector.

Error in load_mgh (line 163)
switch type

Error in MRIread (line 90)
[mri.vol, M, mr_parms, volsz] = load_mgh(fspec,[],[],headeronly);

Error in test_load_mgz (line 2)
mri = MRIread(filepath);

I traced this down to the function load_mgh.m (/Applications/freesurfer/7.4.1/matlab/load_mgh.m) where a file path string 

(char array) is dynamically populated with randomly generated folder names to unzip into. 

It's about line 69 and looks like this:

[status,msg] = unix(sprintf('gunzip -c %s > %s', fname, new_fname));

You may notice that potential spaces in the path names fname and new_fname are not escaped with single quotes. 

I edited the file to escape the parameterized strings like so:

[status,msg] = unix(sprintf("gunzip -c '%s' > '%s'", fname, new_fname));

This solved the problem for me.

Computer details:
OS: MacOS Sonoma (latest)
Chipset: Apple M1 (aarch64)
Calling Program: Matlab R2023b

Freesurfer: 7.4.1

Thank you for your time.

Sincerely,

Tyler Slouf

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