Is there any way to retrieve a dependency tree from yum?

Question

To reduce the chance of the XY problem, I'm trying to install PostGIS on a clean, virtual RHEL5 installation with heavy restrictions. I do not know if we (as a company) have a RH subscription.

# yum install postgis Loaded plugins: product-id, security, subscription-manager This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register. Setting up Install Process No package postgis available. Nothing to do. 

It throws the same error when I try to install emacs, so I'm relatively certain that it doesn't matter which package I'm trying to install.

The VM has internet access.

All I want to do is retrieve a complete dependency graph for a piece of software I specify (obviously, i.e. postgis). yum must already compute this dependency graph (or have one available for retrieval) to do its job, so how can I tap into this resource?

Answer 1

Per the RHEL5 manual pages: "repoquery is a program for querying information from YUM repositories similarly to rpm queries."

For your specific case of postgis:

# repoquery --requires --recursive --resolve  postgis postgresql-libs-0:8.1.23-6.el5_8.i386 geos-0:2.2.3-3.el5.i386 glibc-0:2.5-107.el5_9.5.i686 proj-0:4.5.0-3.el5.i386 

You can drop the ".i386" and ".i686" off of the package names if your system is 64-bit.

The output from repoquery is not perfect since, for example, it fails to list glibc-common in the above list. But your system would not be running if it did not have both glibc and glibc-common already installed.

EDIT: Although it does not cause an error, the --recursive flag appears to do nothing in RHEL5.11 and can be omitted. Also, use the --pkgnarrow=all flag to ensure that all (installed, available, etc) packages are considered for the query. Lastly, for one step of recursion to get more of the dependency tree, in a bash shell, pass the output of the repoquery command to a second repoquery command using tee and xargs like so:

# repoquery --requires  --resolve --pkgnarrow=all postgis.i386 | tee >(xargs -r -n 1 -- repoquery --requires  --resolve --pkgnarrow=all) | sort | uniq basesystem-0:8.0-5.1.1.noarch geos-0:2.2.3-3.el5.i386 glibc-0:2.5-123.el5_11.3.i686 glibc-common-0:2.5-123.el5_11.3.i386 krb5-libs-0:1.6.1-80.el5_11.i386 libgcc-0:4.1.2-55.el5.i386 libstdc++-0:4.1.2-55.el5.i386 openssl-0:0.9.8e-40.el5_11.i686 postgresql-libs-0:8.1.23-10.el5_10.i386 proj-0:4.5.0-3.el5.i386