I recently downloaded the Haskell Platform from the Haskell website. Under the suggestion of the newer answers in this, I blindly ran brew install ghc cabal-install and cabal install cabal cabal-install. Did I install two versions of Haskell on my machine? What should I do to fix any problems?
It doesn't necessarily lead to problems to have multiple versions (I think I have three different versions installed). If you need the disk space uninstall one of the two (instructions for the brew one, for the packaged platform it seems you should be able to use the command sudo uninstall-hs but check it yourself first). If you don't mind the lost disk space, you only have to make sure you have your PATH set up correctly, with the directory containing the ghc binary you want to use in your PATH, before the directory of the other one.
Also, cabal install cabal-install (which you might need to run to update cabal) tends to install cabal in a different place than the platform/brew do, so there, again, you need to make sure your PATH is appropriately set. Normally cabal installs executables in ~/.cabal/bin (local installs) or /usr/local/bin (global installs). The directory containing cabal should go before the others, because an old version of cabal might stick around and you want the new one to be found first.
You probably know this but you can use which ghc and which cabal to check the location of the executable actually being used.
To make things even more complicated, lately it's popular to use Stack, which can also install ghc for you (I find this very convenient, everything is kept in a very controlled environment). So depending on your experience/use case this might be worth looking at as well (but if you just want to try Haskell I recommend you stick with the platform or the brew installation).
Related
Currently, I am using GHC 7.10.1 on my ubuntu 14.04 system, just now I got noticed from mailing list that a new version containing a lot of bug fixes has been released. So I am considering updating my GHC.
I know how to install GHC, however, I have little knowledge about how to deal with packages I have already installed through cabal. It seems that those packages were installed into ~/.cabal, for example, libs were installed into ~/.cabal/lib/x86_64-linux-ghc-7.10.1 and registered in ~/.ghc/x86_64-linux-7.10.1.
The path name(...x86_64-linux-7.10.1...) seems to be suggesting that they could only be used by GHC 7.10.1, so if I want to use a new version GHC and remove the old ghc 7.10.1 from my system, should I clean them up and reinstall those packages?
for example, should I rm -rf ~/.cabal && rm -rf ~/.ghc and reinstall both cabal and GHC? or should I just leave those packages there? if so, would those installed packages get reused by the new GHC?
Yes, you need to reinstall the packages when you update the compiler.
However, if you delete ~/.ghc then that removes the packages from GHC's point of view. You can also delete ~/.cabal and reinstall everything, but binaries in ~/.cabal/bin (including cabal) will usually still work, so often it's easier to keep these and save some time (have a look to see what's there). There might be problems with some - I think some binaries may have the GHC path hard coded internally, so will break, but you can always reinstall them.
~/.cabal/packages contains cached downloads so it's up to you whether you delete that. The data will just be pulled down again next time your run cabal. If in doubt just delete it.
You should delete ~/.cabal/lib which contains the compiled packages and won't be compatible with a different GHC. Likewise for ~/.cabal/share.
Unless you've edited your ~/.cabal/config file by hand and want to keep the changes you can delete that too and a new one will be created.
You don't need to remove anything. If you install GHC 7.10.2 in the same location that you installed GHC 7.10.1, then all the symlinks ghc, ghci, ghc-pkg etc. will be overwritten to point to 7.10.2, but you can still run the versioned programs ghc-7.10.1, ghci-7.10.1, ghc-pkg-7.10.1, etc., or tell cabal to build with a specific compiler with the -w flag. All libraries and library registration information (whether they came with GHC, are installed in the user package database, or are in a sandbox) are (by default) stored under GHC version-specific subdirectories, so different versions of GHC will not interfere with each other.
If you're not running low on disk space I would suggest not removing GHC 7.10.1. After all 7.10.2 was released just yesterday, and if you encounter a strange issue with 7.10.2, it might be worth checking whether 7.10.1 was also affected.
I have the 3.0.1 version of Alex installed on my /usr/bin. I think the Haskell Platform originally put it there (although I'm not 100% sure...).
Unfortunately, version 3.0.1 is bugged so I need to upgrade it to 3.0.5. I tried using cabal to install the latest version of Alex but cabal install alex-3.0.5 it installed the executable on .cabal/bin over on my home folder instead of on /usr/bin
Do I just manually copy the executable to /usr/bin? (that sound like a lot of trouble to do all the time)
Do I change my PATH environment variable so that .cabal/bin comes before /usr/bin? (I'm afraid that an "ls" executable or similar over on the cabal folder might end up messing up my system)
Or is there a simpler way to go at it in general?
I want to first point out the layout that works well for me, and then suggest how you might proceed in your particular situation.
What works well for me
In general, I think that a better layout is to have the following search path:
directories with important non-Haskell related binaries
directory that cabal install installs to
directory that binaries from the Haskell platform are in
This way, you can use cabal install to update binaries from the Haskell platform, but they cannot accidently shadow some non-Haskell related binary.
(On my Windows machine, this layout is easy to achieve, because the binaries from the Haskell platform are installed in a separate directory by default. So I just manually adapt the search path and that's it. I don't know how to achieve it on other platforms).
Suggestion for your particular situation
In your specific situation with the Haskell platform binaries already installed together with the non-Haskell related binaries, maybe you can use the following layout for the search path:
directory containing links to some of the binaries in 3
directory with important non-Haskell related binaries and Haskell platform binaries
directory that cabal install installs to.
This way, binaries from cabal install cannot accidently shadow the important stuff in 2. But if you decide you want to shadow something form the Haskell platform, you can manually add a link to 1. If it's a soft link, I think you only have to do that once per program name, and then you can call cabal install for that program to update it. You could even look up what executables are bundled with the Haskell platform and do that once and for all.
On second though, putting /.cabal/bin in front of /usr/bin in the PATH is simpler and is what most people do already.
Its also not a big deal since only cabal will put files in .cabal/bin so it should be predictable and with little risk of overwriting stuff.
I'm on OSX 10.6 and I have platform 2010.2.0.0 currently. Should I just install 2011.2.0.1 on top or is there an update mechanism that will be smoother?
I've definitely had bumpy upgrade experiences with the Haskell Platform. If you have enough trouble that you just want to wipe the thing and start fresh (you wouldn't be the first!), take a look here:
Everywhere that GHC/Haskell Platform installs
As far as I know there is no update mechanism. And I have never had any trouble with just installing one platform version on top of the other on OSX.
I come from the future (06/2013) and I just had to nuke my entire installation of the haskell platform in order to successfully install a newer. So... there's still no smooth way of upgrading. (At least in OS X)
Whether you need to nuke the existing platform depends on where cabal is configured to install packages.
On Mac OS X, the supplied cabal-install is modified to create a config which separates packages by GHC version. If that's the config you used, you can just install the Haskell Platform on top of the old one.
install-dirs user
prefix: /Users/pgiarrusso/Library/Haskell/$compiler/lib/$pkgid
-- [...]
install-dirs global
prefix: /Library/Haskell/$compiler/lib/$pkgid
Installation-specific binaries, like the ones from gtk2hs-buildtools, are only separated with a configuration like the above. As far as I can tell, at least the actual package register (in ~/.ghc/$GHC_VERSION, used by ghc-pkg and cabal) is instead always per-GHC-version.
The config generated by a vanilla cabal-install (from Hackage) does not take such precautions.
install-dirs user
-- prefix: /Users/pgiarrusso/.cabal
[...]
install-dirs global
-- prefix: /usr/local
If you have such a config, I expect you're going to get trouble unless you remove at least the data in ~/.cabal, and also the binaries in /usr/local from the old Haskell Platform — but don't nuke the whole directory, since /usr/local is often used for installing other software!
The default config is only generated when no config exists, so to update the config you need to move away the existing one.
Over here is the only reason I can find that packages I'm installing using cabal are not being found by GHC:
This happens when you install a package globally, and the previous packages were installed locally. Note that cabal-install install locally by default [...]
Presumably, "local installation" means putting packages in ~/.cabal/. First question: where are global installs?
I've been running cabal using sudo, so I guess that's a global install? The reason I've been doing this is that it complains about permissions when run without sudo, so this contradicts the statement "cabal-install install locally by default". Second question: how do I install locally and how do I install globally?
Trying to fix this mess, I've been randomly using sudo ghc-pkg unregister and randomly removing stuff from ~/.cabal/. Consequently my package tree is broken, probably locally and globally. Third question: How do I start again?
Edit: I'm running Ubuntu 10.10. I installed the Haskell Platform 2011.
Are you using Windows, OS X or some version of Linux? Are you using the Haskell Platform? Have you had a version of ghc or cabal before? For a Linux distribution, subtleties about your package manager may come in, of course. (Traces of an old ghc in particular, and an old ~/.ghc/ directory can be a source of trouble.)
Here are a few elementary thoughts of the type one goes through on #haskell with such problems. (My comprehension is not completely adequate, of course):
The chief question seems to be, Why you were being invited to do what should be local installs with sudo? A global install (cabal install pony --global) would of course require privileges if ghc and its libraries are in /usr/... or some other protected place, but otherwise sudo vs non-sudo is independent of the place of installation. What you do with cabal install pony --user (--user is the default, in theory) should not require superuser authority. (I have sometimes found on OS X that privileges are requested where the gcc needs to be called, but this has usually been due to curiosities about my setup.) But in any case sudo doesn't affect where cabal is putting them: the implicit --user and explicit --global, and more specific incantations for development, do that.
If you do ghc-pkg list, for example, it will divide the packages into the different places they are registered in according to two or more package.conf.d directories it is summarizing. On my laptop at the moment these are
/Users/applicative/.ghc/x86_64-darwin-7.0.3/package.conf.d/...
for the local things in ~/.cabal/lib/... and the protected
/Library/Frameworks/GHC.framework/Versions/7.0.3-x86_64/usr/lib/ghc-7.0.3/package.conf.d
for things that were installed globally with the Haskell Platform installer (this location involves some OS X peculiarities, ghc, ghci and so on are in the woods somewhere, but symlinked to /usr/bin). The conf files for different packages tell you exactly where the libraries were installed. So, for example about the sacred base library,
$ cat base-4.3.1.0-f5c465200a37a65ca26c5c6c600f6c76.conf
tells me:
import-dirs:
/Library/Frameworks/GHC.framework/Versions/7.0.3-x86_64/usr/lib/ghc-7.0.3/base-4.3.1.0
library-dirs:
/Library/Frameworks/GHC.framework/Versions/7.0.3-x86_64/usr/lib/ghc-7.0.3/base-4.3.1.0
In any case, where does ghc-pkg list say your cabal install-ed packages are going? In the ~/.cabal folder, look at the file config. If you haven't edited it, I think the commented and uncommented lines, if they state a preference, are stating the defaults for installation with --global and --user. In the ~.ghc/ directory check out the subdirectory myghcversion/package.conf.d and see if anything is there, which should be the same as what ghc-pkg tells you. (You might study the options for ghc-pkg in general, eg. ghc-pkg check and ghc-pkg recache, if you haven't. You may have installed something in some odd way.)
If you installed ghc and cabal and co. by installing the Haskell Platform with a binary installer or your package manager, which seems like a good idea, it is also a good idea, I think, to keep the Platform libraries as something sacred, and make sure you never install anything globally from Hackage; among other things this is likely to have you overwriting Platform libraries -- though this doesn't seem the difficulty here: it would be more obvious if it were.
I'm looking into trying to find an easy way to manage packages compiled from source so that when it comes time to upgrade, I'm not in a huge mess trying to uninstall/install the new package.
I found a utility called CheckInstall, but it seems to be quite old, and I was wondering if this a reliable solution before I begin using it?
http://www.asic-linux.com.mx/~izto/checkinstall/
Also would simply likely to know any other methods/utilities that you use to handle these installations from source?
Whatever you do, make sure that you eventually go through your distribution's package management system (e.g. rpm for Fedora/Mandriva/RH/SuSE, dpkg for Debian/Ubuntu etc). Otherwise your package manager will not know anything about the packages you installed by hand and you will have unsatisfied dependencies at best, or the mother of all messes at worst.
If you don't have a package manager, then get one and stick with it!
I would suggest that you learn to make your own packages. You can start by having a look at the source packages of your distribution. In fact, if all you want to do is upgrade to version 1.2.3 of MyPackage, your distribution's source package for 1.2.2 can usually be adapted with a simple version change (unless there are patches, but that's another story...).
Unless you want distribution-quality packages (e.g. split library/application/debugging packages, multiple-architecture support etc) it is usually easy to convert your typical configure & make & make install scenario into a proper source package. If you can convince your package to install into a directory rather than /, you are usually done.
As for checkinstall, I have used it in the past, and it worked for a couple of simple packages, but I did not like the fact that it actually let the package install itself onto my system before creating the rpm/deb package. It just tracked which files got installed so that it would package them, which did not protect against unwelcome changes. Oh, and it needed root prilileges to work, which is another main sticking point for me. And lets not go into what happens with statically linked core utilities...
Most tools of the kind seem to work that way, so I simply learnt to build my own packages The Right Way (TM) and let checkinstall and friends mess around elsewhere. If you are still interested, however, there is a list of similar programs here:
http://www.dwheeler.com/essays/automating-destdir.html
PS: BTW checkinstall was updated at the end of 2009, which probably means that it's still adequately current.
EDIT:
In my opinion, the easiest way to perform an upgrade to the latest version of a package if it is not readily available in a repository is to alter the source package of the latest version in your distribution. E.g. for Centos the source packages for the latest version are here:
http://mirror.centos.org/centos/5.5/os/SRPMS/
http://mirror.centos.org/centos/5.5/updates/SRPMS/
...
If you want to upgrade e.g. php, you get the latest SRPM for your distrbution e.g. php-5.1.6-27.el5.src.rpm. Then you do:
rpm -hiv php-5.1.6-27.el5.src.rpm
which installs the source package (just the sources - it does not compile anything). Then you go to the rpm build directory (on my mandriva system its /usr/src/rpm), you copy the latest php source tarball to the SOURCES subdirectory and you make sure it's compressed in the same way as the tarball that just got installed there. Afterwards you edit the php.spec file in the SPECS directory to change the package version and build the binary package with something like:
rpmbuild -ba php.spec
In many cases that's all it will take for a new package. In others things might get a bit more complicated - if there are patches or if there are some major changes in the package you might have to do more.
I suggest you read up on the rpm and rpmbuild commands (their manpages are quite good, in a bit extensive) and check up the documentation on writing spec files. Even if you decide to rely on official backport repositories, it is useful to know how to build your own packages. See also:
http://www.rpm.org/wiki/Docs
EDIT 2:
If you are already installing packages from source, using rpm will actually simplify the building process in the long term, apart from maintaining the integrity of your system. The reason for this is that you won't have to remember the quirks of each package on your own ("oooh, right, now I remember, foo needs me to add -lbar to its CFLAGS"), as the build process will be in the .spec file, which you could imagine as a somewhat structured build script.
As far as upgrading goes, if you already have a .spec file for a previous version of the package, there are two main issues that you may encounter, but both exist whether you use rpm to build your package or not:
A patch that was applied to the previous version by the distribution does not apply any more. In many cases the patch has already been applied to the upstream package, so you can simply drop it. In others you may have to edit it - or I suppose if you deem it unimportant you can drop it too.
The package changed in some major way which affected e.g. the layout of the files it installs. You do read the release notes notes for each new version, don't you?
Other than these two issues, upgrading often boils down to just changing a version number in the spec file and running rpmbuild - even easier than installing from a tarball.
I would suggest that you have a look at the tutorials or at the source package for some simple piece of software such as:
http://mirror.centos.org/centos/5.5/os/SRPMS/ipv6calc-0.61-1.src.rpm
http://mirror.centos.org/centos/5.5/os/SRPMS/libevent-1.4.13-1.src.rpm
If you have experience in buildling packages from a tarball, using rpm to build software is not much of a leap really. It will never be as simple as installing a premade binary package, however.
I use checkinstall on Debian. It should not be so different on CentOS. I use it like that:
./configure
make
sudo checkinstall make install # fakeroot in place of sudo works usally for more security
# install the package generated