On my obscure configuration (GHC 6.10.1, with pkgenv activated, on Fedora Linux rawhide running on a VirtualBox x86 VM with hardware virtualisation enabled), running strace on cabal causes it to misbehave, as described below. I don't know whether this is due to a bug in cabal, the GHC runtime, strace, the Linux kernel, VirtualBox, or my processor's virtualization support. Not sure how to proceed to debug this. Perhaps someone else could try this, on their configuration, and report what they find? This command is ran in an untarred copy of hs-bibutils 0.1 (not that it matters): strace -f -e trace=file cabal install --extra-include-dirs=../bibutils_4.1/lib/ 2>&1|cat >cabal.strace Cabal fails to determine the version of ghc-pkg (or sometimes ghc), and stops, complaining that it can't verify that the version of ghc(-pkg) is the required one. ghc-pkg is execve'd, but something goes wrong - not sure what. -- Robin