GetFileReader reads an input file, gzipped or plain text, and returns an io.Reader for line scanning, along with the file handle, that needs to be closed after reading.

IsFile returns true if the given file exists (as a file or as a directory).

ReadFileToLines Read a file into a list of lines.

ReadFileToString Read a file into a string using ioutil.ReadFile (keeping final newline, if any).

ReadStdinToLines Read stdin into a list of lines.

ReadStdinToString Read stdin into a string using ioutil.ReadFile (removing final newline, if any).