os.Stat

The os.Stat function attempts to resolve the path relative to the root of your project directory. If a matching file or directory is not found, it will attempt to resolve the path relative to the contentDir. A leading path separator (/) is optional.

{{ $f := os.Stat "README.md" }}
{{ $f.IsDir }}    → false (bool)
{{ $f.ModTime }}  → 2021-11-25 10:06:49.315429236 -0800 PST (time.Time)
{{ $f.Name }}     → README.md (string)
{{ $f.Size }}     → 241 (int64)

{{ $d := os.Stat "content" }}
{{ $d.IsDir }}    → true (bool)

Details of the FileInfo structure are available in the Go documentation.