```
embulk preview -G conf.yml
2015-10-07 09:11:14.928 +0900: Embulk v0.7.5
2015-10-07 09:11:16.310 +0900 [INFO] (preview): Loaded plugin embulk-filter-eval (0.1.0)
2015-10-07 09:11:16.330 +0900 [INFO] (preview): Listing local files at directory '/private/tmp/sample/csv' filtering filename by prefix 'sample_'
2015-10-07 09:11:16.336 +0900 [INFO] (preview): Loading files [/private/tmp/sample/csv/sample_01.csv]
*************************** 1 ***************************
      id (     long) : 1
 account (     long) : 32,864
    time (timestamp) : 2015-01-27 19:23:49 UTC
purchase (timestamp) : 2015-01-27 00:00:00 UTC
 comment (   string) : これはテストです
*************************** 2 ***************************
      id (     long) : 2
 account (     long) : 14,824
    time (timestamp) : 2015-01-27 19:01:23 UTC
purchase (timestamp) : 2015-01-27 00:00:00 UTC
 comment (   string) : これはテストです
*************************** 3 ***************************
      id (     long) : 3
 account (     long) : 27,559
    time (timestamp) : 2015-01-28 02:20:02 UTC
purchase (timestamp) : 2015-01-28 00:00:00 UTC
 comment (   string) : これはテストです
```