code: func CommandContext(ctx context.Context, name string, args ...string) *LogCmd {
  	return &LogCmd{
  		Cmd:      exec.CommandContext(ctx, name, args...),
  		Severity: log.LvInfo,
  		Fields:   FieldsFromContext(ctx),
  	}
  }
docs: // CommandContext is similar to exec.CommandContext,
  // but returns *LogCmd with its Context set to ctx.
  //
  // LogCmd.Severity is set to log.LvInfo.
  //
  // LogCmd.Logger is left nil.  If you want to use another logger,
  // set it manually.