Add a release-checking script

Vagrantfile

@@ -568,5 +568,11 @@ Vagrant.configure(2) do |config|
       v.memory = 384
       v.cpus = 1
     end
+
+    # Well, we do need *one* dependency...
+    config.vm.provision :shell, privileged: true, inline: <<-EOF
+      set -xe
+      apt-get install -qq -o=Dpkg::Use-Pty=0 -y unzip
+    EOF
   end
 end

devtools/dev-download-and-check-release.sh

@@ -0,0 +1,51 @@
+# This script downloads the published versions of exa from GitHub and my site,
+# checks that the checksums match, and makes sure the files at least unzip and
+# execute okay.
+#
+# The argument should be of the form “0.8.0”, no ‘v’. That version was the
+# first one to offer checksums, so it’s the minimum version that can be tested.
+
+set +x
+trap 'exit' ERR
+
+exa_version=$1
+if [[ -z "$exa_version" ]]; then
+    echo "Please specify a version, such as '$0 0.8.0'"
+    exit 1
+fi
+
+
+# Delete anything that already exists
+rm -rfv "/tmp/${exa_version}-downloads"
+
+
+# Create a temporary directory and download exa into it
+mkdir "/tmp/${exa_version}-downloads"
+cd "/tmp/${exa_version}-downloads"
+
+echo -e "\n\033[4mDownloading stuff...\033[0m"
+wget --quiet --show-progress "https://github.com/ogham/exa/releases/download/v${exa_version}/exa-macos-x86_64-${exa_version}.zip"
+wget --quiet --show-progress "https://github.com/ogham/exa/releases/download/v${exa_version}/exa-linux-x86_64-${exa_version}.zip"
+
+wget --quiet --show-progress "https://github.com/ogham/exa/releases/download/v${exa_version}/MD5SUMS"
+wget --quiet --show-progress "https://github.com/ogham/exa/releases/download/v${exa_version}/SHA1SUMS"
+
+
+# Unzip the zips and check the sums
+echo -e "\n\033[4mExtracting that stuff...\033[0m"
+unzip "exa-macos-x86_64-${exa_version}.zip"
+unzip "exa-linux-x86_64-${exa_version}.zip"
+
+echo -e "\n\033[4mValidating MD5 checksums...\033[0m"
+md5sum -c MD5SUMS
+
+echo -e "\n\033[4mValidating SHA1 checksums...\033[0m"
+sha1sum -c SHA1SUMS
+
+
+# Finally, give the Linux version a go
+echo -e "\n\033[4mChecking it actually runs...\033[0m"
+./"exa-linux-x86_64" --version
+./"exa-linux-x86_64" --long
+
+echo -e "\n\033[1;32mAll's lookin' good!\033[0m"