[R-Forge #5418] Add a hint that a file might just not exist to fread

[arunsrinivasan]

Submitted by: Stefan Fritsch; Assigned to: Nobody; R-Forge link

Hi

Today, I tried to track a "mysterious" bug in fread when the code of one of my colleagues just stopped working with the error (by cmd.exe) that .. was not a recognized command, that some temp file was empty, etc.

The explanation was of course that she'd moved the .csv and that fread interpreted the path as a shell command because it couldn't find the file. It would be nice if that was added to the error message. E.g.:

Input does not seem to be a file or shell command.

Are you sure the file you want to open exists and there is no typo in the file name or command?
Trying to interpret the input parameter as a shell command returned the error:

# '..' is not recognized as an internal or external command,
# operable program or batch file."

Thanks a lot.