linux下修改ls顯示的時間格式

問題引入

在linux工作時經常會遇到需要定時監控文件變化的情況（如文件更新，數據大小變化等），系統默認ls -l顯示只精確到分鐘，如果能夠精確到秒就非常方便直觀了，因此我嘗試修改ls顯示格式來實現，如下：

1.系統默認顯示格式

[liul@test dataload]$ ls -l
total 28896
drwxr-xr-x 8 liul liul     4096 Sep 24 17:10 PyYAML-3.10
-rw-r--r-- 1 liul liul   241524 Sep 24 16:40 PyYAML-3.10.tar.gz
-rwxr-xr-x 1 liul liul 14466821 Feb 16  2012 greenplum-loaders-4.2.1.0-build-2-RHEL5-x86_64.bin
-rw-r--r-- 1 liul liul 14304561 Mar  1  2012 greenplum-loaders-4.2.1.0-build-2-RHEL5-x86_64.zip
drwxrwxr-x 5 liul liul     4096 Oct  9 17:53 install
drwxrwxr-x 2 liul liul     4096 Oct  9 17:58 shell
drwxr-xr-x 8 liul liul     4096 Oct  9 23:51 yaml-0.1.4
-rw-r--r-- 1 liul liul   471759 Sep 24 16:47 yaml-0.1.4.tar.gz

2.修改ls顯示格式後效果

[liul@test dataload]$ ls -l --time-style '+%Y/%m/%d %H:%M:%S'
total 28896
drwxr-xr-x 8 liul liul     4096 2012/09/24 17:10:17 PyYAML-3.10
-rw-r--r-- 1 liul liul   241524 2012/09/24 16:40:10 PyYAML-3.10.tar.gz
-rwxr-xr-x 1 liul liul 14466821 2012/02/16 00:23:25 greenplum-loaders-4.2.1.0-build-2-RHEL5-x86_64.bin
-rw-r--r-- 1 liul liul 14304561 2012/03/01 17:14:16 greenplum-loaders-4.2.1.0-build-2-RHEL5-x86_64.zip
drwxrwxr-x 5 liul liul     4096 2012/10/09 17:53:00 install
drwxrwxr-x 2 liul liul     4096 2012/10/09 17:58:26 shell
drwxr-xr-x 8 liul liul     4096 2012/10/09 23:51:18 yaml-0.1.4
-rw-r--r-- 1 liul liul   471759 2012/09/24 16:47:13 yaml-0.1.4.tar.gz

2.1 修改配置到bash_profile

[liul@test dataload]$ vi ~/.bash_profile 
[liul@test dataload]$ source ~/.bash_profile 
[liul@test dataload]$ cat ~/.bash_profile | grep TIME
export TIME_STYLE='+%Y/%m/%d %H:%M:%S'
[liul@test dataload]$ source ~/.bash_profile

2.2 系統變量生效

[liul@test dataload]$ ls -l
total 28896
drwxr-xr-x 8 liul liul     4096 2012/09/24 17:10:17 PyYAML-3.10
-rw-r--r-- 1 liul liul   241524 2012/09/24 16:40:10 PyYAML-3.10.tar.gz
-rwxr-xr-x 1 liul liul 14466821 2012/02/16 00:23:25 greenplum-loaders-4.2.1.0-build-2-RHEL5-x86_64.bin
-rw-r--r-- 1 liul liul 14304561 2012/03/01 17:14:16 greenplum-loaders-4.2.1.0-build-2-RHEL5-x86_64.zip
drwxrwxr-x 5 liul liul     4096 2012/10/09 17:53:00 install
drwxrwxr-x 2 liul liul     4096 2012/10/09 17:58:26 shell
drwxr-xr-x 8 liul liul     4096 2012/10/09 23:51:18 yaml-0.1.4
-rw-r--r-- 1 liul liul   471759 2012/09/24 16:47:13 yaml-0.1.4.tar.gz
[liul@test dataload]$

這樣，在使用watch -n 1 ls -l dataload命令時就可以直觀的查看精確到秒級的變化了。