What Does Exit Code Mean?
An exit code or exit status is a number that is returned by an executable to show whether it was successful. This is also sometimes called a return code, or in some cases, an error code, although the terminology here may be slightly different.
Techopedia Explains Exit Code
The simple explanation for an exit code is that the executable program is programmed to return a whole number that shows whether it was successfully executed. In general, zero is usually the signal for successful execution, and numbers from 1-255 represent various negative outcomes or problems.
The terminology for exit code is somewhat confusing, as people may call error codes "return codes" or "exit codes." In any case, interpreting those numbers helps observers to understand why a program crashed, for example, in the infamous Microsoft "blue screen of death" scenario where savvy users can glean information from the text output displayed.
One of the important distinctions in exit codes is the existence of syntax errors versus errors in compiling. As computing grew more complicated, the number of potential errors or outcomes has risen, being reflected in the technologies that produce and interpret exit codes.
There are also different types of debugging involved.