updating cabal-install, but version is not changed

Question

1. Currently I am using cabal-install 1.16.0 I tried to update cabal-install because someone told me that newer version of ghc (7.6.1) is available. Installation result was quite successful except for this message.

   Warning: could not create a symlink in /Users/MyName/Library/Haskell/bin for cabal because the file exists there already but is not managed by cabal. You can create a symlink for this executable manually if you wish. The executable file has been installed at /Users/MyName/Library/Haskell/ghc-7.4.1/lib/cabal-install-1.16.0.2/bin/cabal

   I checked those locations and there was files. So installation was ok.

2. Based on the warning message I got, I tried to create symlinks in /Users/MyName/Library/Haskell/bin by typing this.

   ln -s /Users/MyName/Library/Haskell/bin /Users/MyName/Library/Haskell/ghc-7.4.1/lib/cabal-install-1.16.0.2/bin/cabal

   but It gives me simple, but frustrating message. "File Exists"

3. So I tried again, with existing file removed by Finder. (I just move symlink file to recycle bin.) but machine gives me same message. "File Exists"

4. As a result, I still have installed folder, but not working Cabal, which keep urges me to update. (version 1.16.0)

How can I solve this problem?

Answer 1

I realize this question was asked 6 months ago, I hope you've already found the solution. I'm posting the answer here for future reference.

You were almost there. Removing the existing symlink is the correct first step. The next step is to create the new symlink by doing:

ln -s [actual/path/to/cabal] [name_of_symlink]

You seem to have reversed this order, and this causes the "File Exists" error.