Linux 如何连续显示文件的最后几行内容
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/14604397/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
how to continuously display a file of its last several lines of contents
提问by Wen_CSE
I am trying to find a Unix command (combination, maybe) on how to continuously display a file of its last several lines of contents. But during this displaying, I want some of the top lines are always displayed on the screen top when the rolling contents reach the screen top.
我试图找到一个关于如何连续显示文件的最后几行内容的 Unix 命令（可能是组合）。但是在此显示过程中，我希望滚动内容到达屏幕顶部时始终在屏幕顶部显示一些顶部行。
Is that possible?
那可能吗？
(1) Suppose I have file, "job.sta", the first 2 lines are: job name, John's job on 2013-Jan-30,... Tab1, Tab2, Tab3 0, 1, 2, 1, 90, 89 2, 89, 23 ...
(1) 假设我有文件“job.sta”，前两行是：job name, John's job on 2013-Jan-30,... Tab1, Tab2, Tab3 0, 1, 2, 1, 90, 89 2, 89, 23 ...
(2) This file is on its running, its contents are growing, and I don't know what line it's going to end.
(2) 这个文件在运行，内容越来越多，不知道哪一行结束。
(3) So I want to display (always) the first 2 lines when using tail command, when the updating contents reaches a Unix shell screen top. I am using PuTTY at the moment.
(3) 所以我想在使用 tail 命令时（总是）显示前 2 行，当更新内容到达 Unix shell 屏幕顶部时。我目前正在使用 PuTTY。
Reference: http://www.unix.com/unix-dummies-questions-answers/172000-head-tail-how-display-middle-lines.html
参考：http: //www.unix.com/unix-dummies-questions-answers/172000-head-tail-how-display-middle-lines.html
采纳答案by William Pursell
This will update every 2 seconds rather than whenever data is written to the file, but perhaps that's adequate:
这将每 2 秒更新一次，而不是在数据写入文件时更新一次，但这也许就足够了：
watch 'head -n 2 job.sta; tail job.sta'
回答by sameer karjatkar
You try the following combination tail -f filename | head -2
你试试下面的组合tail -f filename | 头-2
回答by user000001
I use this script to achieve the effect you describe
我用这个脚本来实现你描述的效果
!#/bin/bash
while [ 1 ]; do ls -lt data | head -n 30; sleep 3; echo -en "$(tput cuu 30; tput ed)"; done
This runs a command in a loop, and deletes the last lines of the output from the screen before each iteration.
这会在循环中运行一个命令，并在每次迭代之前从屏幕中删除输出的最后几行。
In your case it would look something like
在你的情况下，它看起来像
!#/bin/bash
while [ 1 ] ;# loop forever
do
head -n 2 job.sta ;# display first 2 lines
tail -n 30 job.sta ;# display last 30 lines from file
sleep 3 ;# wait a bit
echo -en "$(tput cuu 32; tput ed)" ;# delete last 32 lines from screen
done
Of course it is a bit ugly before your file reaches 30 lines
当然在你的文件达到30行之前有点难看
Hope that helps
希望有帮助
回答by choroba
You can use screento simulate the expected behaviour:
您可以使用screen来模拟预期的行为：
Run
screen, press Space.Press Ctrl+afollowed by Sto split the screen.
Resize the top window by pressing Ctrl+afollowed by
:resize 4.In the prompt in the top window, enter
head -n2 file.Move to the bottom window by pressing Ctrl+afollowed by Tab.
Start a new screen session by pressing Ctrl+afollowed by c.
In the new prompt, enter
tail -f file.
运行
screen，按Space。按Ctrl+a然后按S分割屏幕。
按Ctrl+a然后按 调整顶部窗口的大小
:resize 4。在顶部窗口的提示中，输入
head -n2 file。按Ctrl+a然后按 移到底部窗口Tab。
按Ctrl+a然后按 开始新的屏幕会话c。
在新提示中，输入
tail -f file.
回答by Andy Lester
You want the multitailprogram, which not only does the split screen stuff but will also do color-coding.
您需要该multitail程序，该程序不仅可以执行分屏操作，还可以执行颜色编码。
回答by wacko413
I use this function all the time to monitor a log file in another terminal window.
我一直使用此功能来监视另一个终端窗口中的日志文件。
tail -f <filename>
I recommend taking it a step forward to look for particular text in the log. Great if you are only interested in seeing some particular entry being written to the file.
我建议向前迈出一步，在日志中查找特定文本。如果您只对查看写入文件的某些特定条目感兴趣，那就太好了。
tail -f <filename> | grep <keyword or pattern>
