我正在尝试在 Mountain Lion 上安装 GraphicsMagick 并遇到问题。我尝试了所有可以在博客和其他 stackoverflow 问题中搜索的东西，但没有任何效果。所以我把我在每个命令上得到的所有错误都放在了这里。请看看并帮助我。
当我跑
brew install graphicsmagick
我明白了
Warning: Could not link jpeg. Unlinking...
Error: The `brew link` step did not complete successfully
The formula built, but is not symlinked into /usr/local
You can try again using `brew link jpeg'
和
Warning: Could not link libpng. Unlinking...
Error: The `brew link` step did not complete successfully
The formula built, but is not symlinked into /usr/local
You can try again using `brew link libpng'
最后我得到了
==> make install
Warning: Could not link graphicsmagick. Unlinking...
Error: The `brew link` step did not complete successfully
The formula built, but is not symlinked into /usr/local
You can try again using `brew link graphicsmagick'
Possible conflicting files are:
==> Summary
/usr/local/Cellar/graphicsmagick/1.3.18: 283 files, 10M, built in 52 seconds
现在，如果我尝试brew link jpeg或brew link libpng收到此错误
Linking /usr/local/Cellar/jpeg/8d... Warning: Could not link jpeg. Unlinking...
Error: Could not symlink file: /usr/local/Cellar/jpeg/8d/bin/wrjpgcom
Target /usr/local/bin/wrjpgcom already exists. You may need to delete it.
To force the link and overwrite all other conflicting files, do:
brew link --overwrite formula_name
To list all files that would be deleted:
brew link --overwrite --dry-run formula_name
如果我通过这样做来尝试覆盖方法brew link --overwrite jpeg。但是' brew link --overwrite libpng'我明白了
Linking /usr/local/Cellar/libpng/1.5.14... Warning: Could not link libpng. Unlinking...
Error: Permission denied - /usr/local/share/man/man5/png.5
之后，当我尝试时，brew link graphicsmagick我得到：
Linking /usr/local/Cellar/graphicsmagick/1.3.18... Warning: Could not link graphicsmagick. Unlinking...
Error: Could not symlink file: /usr/local/Cellar/graphicsmagick/1.3.18/share/man/man5/quantize.5
/usr/local/share/man/man5 is not writable. You should change its permissions.
请帮我。提前致谢。