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How to exit if a command failed?
...on-zero).
Using ( ) makes the command inside them run in a sub-shell and calling a exit from there causes you to exit the sub-shell and not your original shell, hence execution continues in your original shell.
To overcome this use { }
The last two changes are required by bash.
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encryption/decryption with multiple keys
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GnuPG and PGP clients in general usually encrypt the actual data with a symmetric key called a "session key". The session key is then encrypted with each "recipient key" (i.e. the ones you specify with -r/--recipient). This is sometimes referred to as a hybri...
What's wrong with nullable columns in composite primary keys?
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Primary keys are for uniquely identifying rows. This is done by comparing all parts of a key to the input.
Per definition, NULL cannot be part of a successful comparison. Even a comparison to itself (NULL = NULL) will fail. This means a key containing NULL would not work.
Additonally, NULL is al...
When to use reinterpret_cast?
...time hence the word static . This is the cast the C++ compiler uses internally for implicit casts also.
11 Answers
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Display text on MouseOver for image in html
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You can use CSS hover
Link to jsfiddle here: http://jsfiddle.net/ANKwQ/5/
HTML:
<a><img src='https://encrypted-tbn2.google.com/images?q=tbn:ANd9GcQB3a3aouZcIPEF0di4r9uK4c0r9FlFnCasg_P8ISk8tZytippZRQ'></a>
<div>text</div>
CSS:
div {
display: none;
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Linux/Windows批量删除.svn文件夹(svn delete) - 更多技术 - 清泛网 - 专注C/C++及内核技术
...svn" @echo "%%a\.svn"
@for /r . %%a in (.) do @if exist "%%a\.svn" rd /s /q "%%a\.svn"
@echo completed
@pause
方法二：右键菜单“Delete SVN Folders”删除指定目录下的.svn文件夹，需要写注册表
建立一个文本文件，取名为 svn_del.reg（扩展名由txt改为re...
window+nginx+php-cgi的php-cgi线程/子进程问题 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...indows, therefore php-cgi does not spawn children, and when PHP_FCGI_MAX_REQUESTS is reached the process terminates.
Check on PHP's source, file cgi_main.c, around line 1982:
#ifndef PHP_WIN32
/* Pre-fork, if required */
if (getenv("PHP_FCGI_CHILDREN")) {
char * children_str = g...
App Inventor 2 连接调试器的几种方式的比较 - App Inventor 2 中文网 - 清...
...扰、或商业模拟器安装不了，推荐使用AI2Starter模拟器。
Q：商业模拟器如何使用？
https://bbs.tsingfun.com/thread-1741-1-1.html
Q：模拟器有什么不足吗？A：使用模拟器无法完成与真实手机相同的所有操作，例如，无法摇动它、无法拨...
App Inventor 2 要在界面上做一个电量图标，有什么好的思路吗？ - App应用...
...量状态，自己作图，区间多弄一些就可以了。
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Q：但是像我们手机上的电量应该不是分N张图片吧？
A：你要更细致，做100张图，每一格电量对应一张状态图片，不过跟做10张图、每张代表10格电量，体验上几乎没有差别...
AppInventor2 知识产权保护相关问题分享 - App Inventor 2 中文网 - 清泛IT...
Q：AppInventor2开发的APP可以去工信部备案吗？软件可以申请软件著作权吗？
上架小米、华为、v、o的应用商店大致的流程是什么样的
软件开发平台是否是开源的，做出的软件想要盈利是否会有影响？
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