我使用过的Linux命令之tailf - 跟踪日志文件/更好的tail -f版本
我使用过的Linux命令之tailf - 跟踪日志文件/更好的tail -f版本
本文链接：http://codingstandards.iteye.com/blog/832760 ? （转载请注明出处）
用途说明tailf命令几乎等同于tail -f，严格说来应该与tail --follow=name更相似些。当文件改名之后它也能继续跟踪，特别适合于日志文件的跟踪（follow the growth of a log file）。与tail -f不同的是，如果文件不增长，它不会去访问磁盘文件（It is similar to tail -f but does not access the file when it is not growing.? This has the side effect of not updating the access? time for the file, so a filesystem flush does not occur periodically when no log activity is happening.）。tailf特别适合那些便携机上跟踪日志文件，因为它能省电，因为减少了磁盘访问嘛（tailf? is extremely useful for monitoring log files on a laptop when logging is infrequent and the user desires that the hard disk spin down to conserve battery life.）。tailf命令不是个脚本，而是一个用C代码编译后的二进制执行文件，某些Linux安装之后没有这个命令，本文提供了怎么编译安装tailf命令的方法。
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常用参数格式：tailf logfile
动态跟踪日志文件logfile，最初的时候打印文件的最后10行内容。
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使用示例示例一 使用tailf命令跟踪日志[root@web imx_server]# tailf log/WEB.LOG
??????? "seq": 5710,
??????? "clientId": 1291343201649254,
??????? "presenceStatus": "1"
} }})
16:09:21.324 DEBUG http-80-79 hyjc.cometd.CometdServlet - { "cid": 1291343201649002, "op": "recv", "ncc0": 175}
16:09:21.444 DEBUG http-80-32 hyjc.filter.AccessCounterFilter - uri=/imx/cometd/service
16:09:21.506 DEBUG http-80-79 hyjc.filter.AccessCounterFilter - uri=/imx/cometd/service
16:09:23.239 DEBUG http-80-45 hyjc.cometd.CometdServlet - { "cid": 1291343201649184, "op": "recv", "ncc0": 55}
16:09:23.327 DEBUG http-80-45 hyjc.filter.AccessCounterFilter - uri=/imx/cometd/service
16:09:24.288 DEBUG http-80-145 hyjc.cometd.CometdServlet - { "cid": 1291283017076175, "op": "recv", "ncc0": 82}
16:09:24.339 DEBUG http-80-81 hyjc.cometd.CometdServlet - { "cid": 1291283017076151, "op": "recv", "ncc0": 142}
16:09:24.360 DEBUG http-80-64 hyjc.cometd.CometdServlet - { "cid": 1291343201649090, "op": "recv", "ncc0": 40}
16:09:24.359 DEBUG http-80-143 hyjc.cometd.CometdServlet - { "cid": 1291283017076176, "op": "recv", "ncc0": 66}
16:09:24.878 DEBUG http-80-145 hyjc.filter.AccessCounterFilter - uri=/imx/cometd/service
16:09:24.892 DEBUG http-80-143 hyjc.filter.AccessCounterFilter - uri=/imx/cometd/service
16:09:24.896 DEBUG http-80-64 hyjc.filter.AccessCounterFilter - uri=/imx/cometd/service
16:09:24.906 DEBUG http-80-81 hyjc.filter.AccessCounterFilter - uri=/imx/cometd/service
16:09:25.095 DEBUG http-80-115 hyjc.filter.AccessCounterFilter - uri=/imx/cometd/service
16:09:25.095 DEBUG http-80-115 hyjc.cometd.CometdServlet - msgType IMX_ACTIVE_TEST msgBody {"clientId":1291343201649002,"presenceStatus":"1","seq":385}
16:09:25.095? INFO http-80-115 imx.client.ImxClient - Tx IMX_ACTIVE_TEST{seq=5711,client_id=1291343201649002,presence_status=1(presence_status_online),}
16:09:25.095 DEBUG http-80-115 hyjc.cometd.CometdServlet - { "cid": 1291343201649002, "op": "send", "sent": 0, "rc": 1, "msg": { "mt": "IMX_ACTIVE_TEST", "mb": {
??????? "seq": 5711,
??????? "clientId": 1291343201649002,
??????? "presenceStatus": "1"
} }}
Ctrl+C
[root@web imx_server]#
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示例二 编译安装tailf命令有些Linux版本不带tailf命令的。
[root@smsgw root]# tailf
-bash: tailf: command not found
[root@smsgw root]#
到代码搜索网站www.koders.com输入tailf.c就可以搜索到源代码
tailf.c结果页面：http://www.koders.com/default.aspx?s=tailf.c&submit=Search&la=*&li=*
tailf.c源码页面：http://www.koders.com/c/fidB6EFAC156A7B4C4A46B38039C79B4AD34939EED0.aspx?s=tailf#L1
点左上角的download就可下载，也可直接下载本文附件tailf.zip。
[root@smsgw tailf]# unzip tailf.zip
Archive:? tailf.zip
? inflating: tailf.c????????????????
[root@smsgw tailf]# ls
tailf.c? tailf.zip
[root@smsgw tailf]# gcc -o /usr/bin/tailf tailf.c
tailf.c:34:17: nls.h: 没有那个文件或目录
tailf.c: In function `tailf':
tailf.c:53: warning: passing arg 2 of `fprintf' makes pointer from integer without a cast
tailf.c: In function `main':
tailf.c:88: `LC_ALL' undeclared (first use in this function)
tailf.c:88: (Each undeclared identifier is reported only once
tailf.c:88: for each function it appears in.)
tailf.c:89: `PACKAGE' undeclared (first use in this function)
tailf.c:89: `LOCALEDIR' undeclared (first use in this function)
tailf.c:93: warning: passing arg 2 of `fprintf' makes pointer from integer without a cast
tailf.c:105: warning: passing arg 2 of `fprintf' makes pointer from integer without a cast
[root@smsgw tailf]#
修改一下tailf.c的源代码。
第34行附近：注释掉头文件，增加宏定义
//#include "nls.h"
#define _(s) s
第89行附近：把原来的代码注释掉
??? //setlocale(LC_ALL, "");
??? //bindtextdomain(PACKAGE, LOCALEDIR);
??? //textdomain(PACKAGE);
看了源代码之后，你是不是发现其实Linux命令其实并不太神秘。
注：本文附件中的tailf.c已经修改成下面的样子。
?[root@smsgw tailf]# gcc -Wall -o /usr/bin/tailf tailf.c
[root@smsgw tailf]# tailf
Usage: tailf logfile
[root@smsgw tailf]#?
问题思考相关资料【1】linuxcommand.org tailf手册页
【2】代码搜索 tailf源代码
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1 楼 superlittlefish 2011-07-03 这个学习了, 以前一直都是用tail -f
