./resttool: line 47: [: -eq: unary operator expected

[dataprolet]

I'm using the tool on MacOS 13.4.1 an simply calling restgetprofile returns the following:

2023-07-31 11:48:02 -- retrieving IrmcConfig/BootConfig from 1.2.3.4
expr: syntax error
./resttool: line 47: [: -eq: unary operator expected
2023-07-31 11:48:02 -- Reading profile - be patient ...
expr: syntax error
./resttool: line 47: [: -eq: unary operator expected
2023-07-31 11:48:02 -- ProfileStoreAdd failed

What is causing this? I assume it's MacOS specific?