If a package's sdist tarball is newer than its cabal-dev installed version, reinstall it

update_sdists.sh

#!/bin/bash

SANDBOX_DIR="cabal-dev"
SDIST_DIR="./sdist/"
SDIST_SUFFIX=".tar.gz"

PACKAGES_CONF_DIR=$SANDBOX_DIR"/packages-"`ghc --numeric-version`".conf/"

find $SDIST_DIR -name *$SDIST_SUFFIX -print0 | while read -d $'\0' sdist_path
do
  file_name=${sdist_path#$SDIST_DIR}
  package_name=${file_name%$SDIST_SUFFIX}
  echo "Checking sdist tarball at" $sdist_path "(package is" $package_name ")"

    find $PACKAGES_CONF_DIR -name $package_name* -print0 | while read -d $'\0' installed_sdist_path
    do
      echo "installed at" $installed_sdist_path
      if [ $installed_sdist_path -nt $sdist_path ]
      then
        echo "... which is newer than latest sdist tarball, ignoring"
      else
        echo "... which is older than latest sdist tarball, re-installing"
        cabal-dev -s $SANDBOX_DIR install $sdist_path
      fi
    done
    echo
done