On Saturday 17 September 2011, 12:41:17, mukesh tiwari wrote:
Does there exist an unversioned ghc? What does
$ which ghc
print?
It prints nothing .
Okay, since cabal defaults to looking for plain "ghc" when no compiler is explicitly passed, that explains why it didn't work without --with-compiler Normally, when ghc is installed, it creates versionless symlinks to the actual scripts/binaries, so there should be symbolic links ghc, ghci, ghc-pkg to the versioned things (and haddock->haddock-ghc-7.2.1, runhaskell->runghc), many programmes expect unversioned tools by default. It might be that your install is broken, but probably creating the symlinks yourself (read the ln man-page and be careful when you create them) will be enough.
ntro@ntro-HP-dx2480-MT-NA121PA:/usr/local/bin$ ls ghc* ghc-7.2.1 ghci-7.2.1 ghc-pkg-7.2.1
Those should be linked to.
ntro@ntro-HP-dx2480-MT-NA121PA:/usr/local/bin$ ls django-admin.py eggy eric4-compare eric4-doc eric4-pluginrepository eric4-re eric4-trpreviewer eric4-webbrowser ghc-pkg-7.2.1 hp2ps runghc spyder Editra eric4 eric4-configure eric4-editor eric4-pluginuninstall eric4-sqlbrowser eric4-uipreviewer ghc-7.2.1 haddock hpc runhaskell UTscapy Editra.pyw eric4-api eric4-diff eric4-plugininstall eric4-qregexp eric4-tray eric4-unittest ghci-7.2.1 haddock-ghc-7.2.1 hsc2hs scapy
So should i delete ghc-6.12.1 from /var/lib
Optional. It shouldn't cause any problems (unless you need the space).
and move the ghc-7.2.1 from /usr/local/lib to /var/lib to execute cabal install <pkg-name> -v --dry-run ?
No, leave /usr/local/lib where it is, moving it would cause massive breakage. For example, /usr/bin/ghc-7.2.1 expects the libraries and binaries there. The only problem was that cabal looked for "ghc" which no longer exists on your path. That fact is somewhat dubious, as normally installing ghc creates the symlinks, but creating them is probably all that's needed if invoking ghc-7.2.1 works.
As /usr/local/bin is already in the path i don't need to move any files from here. Am i correct ?
Don't move anything. If your ghc-7.2.1 is broken, you will need to reinstall (that or another version), otherwise you can work with always using (and passing) the explicit version or, more conveniently, create the expected symlinks. Cheers, Daniel