iOS应用文件夹的明细

沙盒路径

NSHomeDirectory()
/var/mobile/Containers/Data/Application/213DA05A-7967-49A5-83C0-B34C0C626C56 

关于/var文件夹的解释是 "/var" is usually used for log files, 'temporary' files (like mail spool, printer spool, etc), databases, and all other data not tied to a specific user. Logs are usually in "/var/log", databases in "/var/lib" (mysql - "/var/lib/mysql"), etc.
/var 通常用来存储系统运行时日志文件，临时文件和公用数据，从沙盒的路径来看，var文件夹存储了iOS系统中所有app运行后产生的数据，沙盒是一个以唯一字符串命名的文件夹。

临时文件路径

在沙盒下的tmp文件夹中

NSTemporaryDirectory()
/var/mobile/Containers/Data/Application/213DA05A-7967-49A5-83C0-B34C0C626C56/tmp/

app用户的文件夹路径 Documents

[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES) firstObject]
/var/mobile/Containers/Data/Application/213DA05A-7967-49A5-83C0-B34C0C626C56/Documents 

临时库文件夹 Library

[NSSearchPathForDirectoriesInDomains(NSLibraryDirectory,NSUserDomainMask, YES) firstObject]
/var/mobile/Containers/Data/Application/213DA05A-7967-49A5-83C0-B34C0C626C56/Library

缓存文件夹在库文件夹的下一级

[NSSearchPathForDirectoriesInDomains(NSCachesDirectory,NSUserDomainMask, YES) firstObject]
/var/mobile/Containers/Data/Application/213DA05A-7967-49A5-83C0-B34C0C626C56/Library/Caches

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应用的bundle路径 同样也在var文件夹下，按理说应该在usr里的

[[NSBundle mainBundle] bundlePath]
/var/containers/Bundle/Application/37770E10-9334-46D2-AE64-24D0D0D45616/name.app/

总结：

• 沙盒文件夹存储在 unix-like 系统的 /var/mobile/Containers/Data/Application/ 文件夹下 (移动-容器-数据-应用)
• NSBundle mainBundle 的路径是
  /var/containers/Bundle/Application/ 文件夹下(容器-包-应用)
• NSData writetToFile 方法无法在bundle文件夹中进行写入操作,文件夹为只读属性。

补充
info.plist在mainBundle里，所以获取info.plist的方法是

[[NSBundle mainBundle] infoDictionary];

参考链接：1. https://serverfault.com/questions/384342/what-are-the-best-practices-of-the-usr-var-and-etc-folders
2.https://blog.csdn.net/liudukun/article/details/23994039