// All codes interacting with file system should be put here.// Invoke file system operations via afero's Fs interface.// This is convenient for mock testing.packagefileimport("github.com/spf13/afero")// OsFs is a Fs implementation that uses functions provided by the os package.// When in unit testing, replace this with afero.MemMapFs.varFsafero.Fs=afero.OsFs{}