Squid-squid日志转换

Question

有squid日志如下，时间格式为时间戳形式（第一列），想把时间戳转化成日期时间的形式，求简单方法。

1345184908.747      0 123.150.162.10 TCP_IMS_HIT/304 303 GET http://file.abcd.com/images/channel/content/images/share_mail/share_sina.gif - NONE/- image/gif
1345184908.749     43 58.216.147.234 TCP_MEM_HIT/200 28055 GET http://abcdimg.adsame.com/dolphinfile/abcd/2012/07/0_99.gif - NONE/- image/gif
1345184908.754      5 115.192.193.227 TCP_MEM_HIT/200 3210 GET http://file.abcd.com/file/vip/images/share_sina.png - NONE/- image/png
1345184908.757      2 1.24.206.18 TCP_IMS_HIT/304 303 GET http://file.abcd.com/images/channel/content/images/share_mail/share_163.gif - NONE/- image/gif
1345184908.760      0 211.140.5.115 TCP_MEM_HIT/200 7468 GET http://photos.abcd.com/2012-08-16/100424784_1.html? - NONE/- text/html
1345184908.767      0 183.28.87.191 TCP_MEM_HIT/200 7422 GET http://photos.abcd.com/2012-08-13/100423493_2.html - NONE/- text/html
1345184908.768      1 210.75.18.56 TCP_REFRESH_MISS/302 686 GET http://finance.abcd.com/2011-09-17/100303644.html - DIRECT/219.232.244.236 text/html
1345184908.769      0 106.80.185.210 TCP_MEM_HIT/200 874 GET http://file.abcd.com/file/homepage/images/new/bg_lm_bottom.gif - NONE/- image/gif
1345184908.770      0 1.24.206.18 TCP_IMS_HIT/304 303 GET http://file.abcd.com/images/channel/content/images/share_mail/share_douban.gif - NONE/- image/gif
1345184908.783      0 1.24.206.18 TCP_IMS_HIT/304 303 GET http://file.abcd.com/images/channel/content/images/share_mail/share_xianguo.gif - NONE/- image/gif