$HOME 和'~'(波浪号)之间的区别? [英] Difference between $HOME and '~' (tilde)?

问题描述

我一直以为$HOME和~是一模一样的，所以可以可以互换使用.今天，当我尝试安装 pylibmc 时，一个 python绑定到 memcached，在我的共享服务器上使用 ~ 给了我错误但没有$HOME.我想说明原因.

libmemcached 是 pylibmc 的要求.我已经安装了 libmemcached在我的主目录下，因为我在服务器上没有根.结果，到安装 pylibmc，我需要确保安装脚本知道在哪里找到 libmemcached.

执行python setup.py install --with-libmemcached=~时，安装脚本运行

<上一页>gcc -pthread -fno-strict-aliasing -g -O2 -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -fPIC -DUSE_ZLIB -I~/include -I/usr/local/include/python2.7 -c _pylibmcmodule.c -o build/temp.linux-i686-2.7/_pylibmcmodule.o -fno-strict-aliasing

这给出了 libmemcached 找不到的错误.

如果我更改为 --with-libmemcached=$HOME，则脚本运行

<上一页>gcc -pthread -fno-strict-aliasing -g -O2 -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -fPIC -DUSE_ZLIB -I/home/waterbotte/include -I/usr/local/include/python2.7 -c _pylibmcmodule.c -o build/temp.linux-i686-2.7/_pylibmcmodule.o -fno-strict-aliasing

没有任何问题.看起来问题是波浪号没有得到解决.但为什么呢?

解决方案

shell 将 ~ 替换为用户的主目录(update: 或者可能是其他用户，如果 ~ 后跟 / 以外的其他内容)，但前提是它是单词的第一个字符.

--with-libmemcached=~ 的 ~ 不在开头，因此 shell 不理会它.

I had always thought that $HOME and ~ were exactly the same and thus could be used interchangeably. Today, when I tried to install pylibmc, a python binding to memcached, on my shared server the use of ~ gave me error but not $HOME. I would like to reason out why.

libmemcached is a requirement for pylibmc. I have libmemcached installed under my home directory because I have no root on the server. As a result, to install pylibmc, I need to make sure the installation script knows where to find libmemcached.

When executing python setup.py install --with-libmemcached=~, the installation script runs

gcc -pthread -fno-strict-aliasing -g -O2 -DNDEBUG -g -fwrapv -O3 -Wall 
  -Wstrict-prototypes -fPIC -DUSE_ZLIB -I~/include 
  -I/usr/local/include/python2.7 -c _pylibmcmodule.c 
  -o build/temp.linux-i686-2.7/_pylibmcmodule.o -fno-strict-aliasing

which gives the errors that libmemcached can't be found.

If I change to --with-libmemcached=$HOME, the script runs

gcc -pthread -fno-strict-aliasing -g -O2 -DNDEBUG -g -fwrapv -O3 -Wall 
  -Wstrict-prototypes -fPIC -DUSE_ZLIB -I/home/waterbotte/include 
  -I/usr/local/include/python2.7 -c _pylibmcmodule.c 
  -o build/temp.linux-i686-2.7/_pylibmcmodule.o -fno-strict-aliasing

without any problem. It looks like the problem is that tilde doesn't get resolved. But why?

解决方案

The shell replaces ~ with the user's home directory (update: or perhaps by the home directory of some other user, if ~ is followed by something other than a /), but only if it's the first character of a word.

--with-libmemcached=~ has ~ not in the beginning, so the shell leaves it alone.

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