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Why do some compilers use “a.out” as the default name for executables?

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问题 Most UNIX C compilers link executables by default to a file called "a.out". Why? Is this a written standard or just de-facto standard behavior? What would break if these compilers would just produce an error message (or use a different default name) instead of producing "a.out"? 回答1: a.out stands for assembler output. I think that justifies why most compilers have this name as default. More info here. 回答2: A.out is actually the name of an UNIX executable file format. (ELF is another) The

Linux历史命令管理以及用法

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Linux历史命令管理以及用法 history：打印历史记录 1、Linux系统当你在shell(控制台)中输入并执行命令时，shell会自动把你的命令记录到历史列表中，一般保存在用户目录下的.bash_history文件中。默认保存1000条，你也可以更改这个值。（HISTSIZE=需要更改的条数）如果你键入 history, history会向你显示你所使用的前1000个历史命令，并且给它们编了号，你会看到一个用数字编号的列表快速从屏幕上卷过。你可能不需要查看1000个命令中的所有项目, 当然你也可以加入数字来列出最近的 n 笔命令列表。 2、history的作用顾名思义就是记录执行过的命令。 3、history的用法： history [n] n为数字，列出最近的n条命令 -c 将目前shell中的所有history命令消除 history [-raw] histfiles -a 将目前新增的命令写入histfiles, 默认写入~/.bash_history -r 将histfiles内容读入到目前shell的history记忆中 -w 将目前history记忆的内容写入到histfiles 来源： https://blog.csdn.net/qq_27547737/article/details/99231882

HTTP Headers: Controlling Cache and History Mechanism

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问题 I'm trying to figure out the best HTTP headers to send for four use cases. I'm hoping to come up with headers that do not depend on user agent / protocol version sniffing but I'll accept that if nothing else fits. All URLs are fetched through fully custom handler so I can select all headers as I like, this is all about intermediate proxies and user agents . If possible, this should be compatible with both HTTP/1.0 and HTTP/1.1 clients. If multiple solutions exists, the best one will be the

命令历史的管理及用法

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bash可以保存的过去曾经执行过的命令。当某个用户登录到shell中，会读取该用户家目录中的~/.bash_history文件，并将历史命令列表保存到内存中。当用户退出当前shell时，会将内存中的历史命令列表覆盖至~/.bash_history文件。我们可以通过# histroy 来查看历史命令。history是bash的内部命令。通过# help history获取帮助。一、history的常见选项 # history 。。。 # 省略前面 994 man poweroff 995 poweroff --reboot 996 man poweroff 997 man shutdown 998 shutdown +2 "Goodbye SB" 999 shutdown -c 1000 man rm 1001 info rm 1002 man history 1003 enable 1004 enable | grep history 1005 help history 1006 history 1007 history -d 1000 1008 history 1009 echo $HISTORYSIZE 1010 history # history -c 清空命令历史记录 # history -d N N为整数，删除历史中序号是N的命令 # history N N为整数

TSQL: Get Last Queries Ran

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问题 Is there a way to get the SQL text for the last few queries? I am using Microsoft SQL Server 2005 回答1: Yes, take a look, this will give you the 50 most recent executed SQL statements sql 2005 and up only SELECT TOP 50 * FROM(SELECT COALESCE(OBJECT_NAME(s2.objectid),'Ad-Hoc') AS ProcName, execution_count,s2.objectid, (SELECT TOP 1 SUBSTRING(s2.TEXT,statement_start_offset / 2+1 , ( (CASE WHEN statement_end_offset = -1 THEN (LEN(CONVERT(NVARCHAR(MAX),s2.TEXT)) * 2) ELSE statement_end_offset END)

Bash中自动补全时忽略大小写

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编辑~/.inputrc（没有的话，就新建一个），在最后加一行： set completion-ignore- case on 保存，重新打开终端就可以了。补充：在~/.inputrc中加入: “\e[A”: history-search- backward “\e[B”: history -search-forward 能够让你在命令行输入字符之后，就可以用方向键Up，Down来搜索以该串字符开头的历史命令。或者在~/.bashrc中加入： bind ' "\e[A": history-search-backward ' bind ' "\e[B": history-search-forward ' 也能达到同样的效果。参考链接： http://www.cnblogs.com/mopmoq/archive/2009/04/08/1431883.html http://stackoverflow.com/questions/1030182/how-do-i-change-bash-history-completion-to-complete-whats-already-on-the-line http://hints.macworld.com/article.php?story=20031026174236860 https://wiki.archlinux.org

SecurityError: The operation is insecure - window.history.pushState()

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I'm getting this error in Firefox's Console: SecurityError: The operation is insecure and the guilty is HTML5 feature: window.history.pushState() when I try to load something with AJAX. It is supposed to load some data but Javascript stops executing on error. I'm wondering why this may be happening. Is this some server misconfiguration? Any help would be appreciated. UPDATE: Yes, it was a server error with domain name not matching: http://en.wikipedia.org/wiki/Same-origin_policy Matt Make sure you are following the Same Origin Policy . This means same domain, same subdomain, same protocol

Original purpose of <input type=“hidden”>? [closed]

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I am curious about the original purpose of the <input type="hidden"> tag. Nowadays it is often used together with JavaScript to store variables in it which are sent to the server and things like that. HTML 2.0 was released in November 1995 , containing already the specification for input type="hidden" JavaScript was released March 1996 Therefore, the <input type="hidden"> existed before JavaScript, so what was its original purpose? I can only imagine of sending a value from the server to the client which is (unchanged) sent back to maintain a kind of a state. Or do I get something wrong in the

What is the origin of foo and bar? [closed]

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Where did they come from and when were they first used? Hugo tl;dr "Foo" and "bar" as metasyntactic variables were popularised by MIT and DEC, the first references are in work on LISP and PDP-1 and Project MAC from 1964 onwards. Many of these people were in MIT's Tech Model Railroad Club, where we find the first documented use of "foo" in tech circles in 1959 (and a variant in 1958). Both "foo" and "bar" (and even "baz") were well known in popular culture, especially from Smokey Stover and Pogo comics, which will have been read by many TMRC members. Also, it seems likely the military FUBAR

Moving files lose history in TFS 2013

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问题 I'm using VS2013 Update 4 with TFS 2013 Update 4. In Source Control Explorer, whenever I move a file from one folder to another I can see that the file's history is preserved in the new location. However, that history is gone when I check-in the pending changes. The same thing happens when I try to run "tf move" command. So, how can you move a file in TFS and still keep the file's history? 回答1: When a file is renamed correctly, the History is not "Gone", it's associated to the "old name"