history

1、在 /etc/profile 加上一段shell 步骤1、vi /etc/profile 2、i 进入命令行模式 3、在最后加上下面这段文字 history USER=`whoami` USER_IP=`who -u am i 2>/dev/null| awk '{print $NF}'|sed -e 's/[()]//g'` if [ "$USER_IP" = "" ]; then USER_IP=`hostname` fi if [ ! -d /var/log/history ]; then mkdir /var/log/history chmod 777 /var/log/history fi if [ ! -d /var/log/history/${LOGNAME} ]; then mkdir /var/log/history/${LOGNAME} chmod 300 /var/log/history/${LOGNAME} fi export HISTSIZE=4096 DT=`date +"%Y%m%d_%H:%M:%S"` export HISTFILE="/var/log/history/${LOGNAME}/${USER}@${USER_IP}_$DT" chmod 600 /var/log/history/${LOGNAME}/*history* 2>/dev

I use windows 7 64bit. I found both cmd.exe and powershell cannot keep history. It means it lost my command history when I quit the shell. Is there a tools can help cmd.exe or powershell to remember the history? I try to use console 2. Console 2 is tiny and has a tab interface. But console 2 can't remember the history too. Maybe there is another front end can do this. Michael Kelley The answer below is from Keith Hill (PowerShell Microsoft MVP) in his answer to the question powershell history: how do you prevent duplicate commands : BTW if you want to automatically save this on exit you can do

Recently I found this article that claims that the idea to prefer for(;;) over while(1) for infinite loop came because the C compiler originally available on PDP-11 generated an extra machine instruction for while(1) . Btw now even Visual C++ warnings tend to favor the former . How realistic is such attribution of for(;;) idiom? Here's what the V7 Unix compiler cc produces (using SIMH and an image from TUHS ): $ cat>a.c main(){ while(1); } $ cat>b.c main(){ for(;;); } $ cc -S a.c $ cc -S b.c a.c ( while ) compiles to: .globl _main .text _main: ~~main: jsr r5,csv jbr L1 L2:L4:tst $1 jeq L5 jbr

During the last few weeks, I had the opportunity to read two documents: The MPEG-4 Part 2 specification (ISO/IEC 14496-2), which people just call "mpeg-4" The MPEG-4 Part 10 specification (ISO/IEC 14496-10), which is also called "h.264" or "AVC" After having read all the cool ideas in "mpeg-4" like identifying facial expression, motion of limbs of people, and sprites, I got really excited. The ideas sound very fun, maybe even fantastic, for an idea from 1999. But then I read the "h.264" standard, and none of those ideas were there. There was a lot of discussion on how to encode pixels, but

浏览器窗口有一个history对象，用来保存浏览历史。如果当前窗口先后访问了3个网址，那么history对象就包括三项，history.length属性=3 history对象提供了一系列方法，允许在浏览历史之间移动。具体说明如下 back():移动到上一个访问页面，等同于浏览器的后退键 forward():移动到下一个访问页面，等同于浏览器的前进键 go():接受一个整数作为参数，移动到该整数指定的页面，如go(1)相当于forward(),go(-1)相当于back() 如果移动的位置超出了访问历史的边界，以上3个方法并不报错，而是默默失败 history.go(0)相当于刷新当前页面。如： history.go(0) 常用的“返回上一页”连接，代码如下： docuement.getElementById('backLink').onclick=function() { window.history.back(); } 实现无刷新浏览： HTML5为history对象添加了两个新方法，history.pushState()和history.replaceState(),用来在历史中添加和修改记录，用法如下： if(!!(window.history&&history.pushState)) { //支持History API } else { //不支持 }

How did these keywords and concepts come to life? What were the forces and problems that made them appear? What was the first language to have them? Actually, it's not just about public / private / protected , but rather the whole range of keywords that enforce some rules ( abstract , final , internal ). But, please, do not assume things. Answer if you know at least part of the answer or answer if you lived those moments. References are greatly appreciated. Henk Holterman Simula (1967) , considered to be the first OO language, has modifiers called protected and hidden . I assume that public is