1 files changed, 1 insertions, 1 deletions
diff --git a/guides/Rakefile b/guides/Rakefile
index 84e18e0972..4116e6f9cc 100644
--- a/guides/Rakefile
+++ b/guides/Rakefile
@@ -30,7 +30,7 @@ namespace :guides do
       unless Kindlerb.kindlegen_available?
         abort "Please run `setupkindlerb` to install kindlegen"
       end
-      unless `convert` =~ /convert/
+      unless /convert/.match?(`convert`)
         abort "Please install ImageMagick"
       end
       ENV["KINDLE"] = "1"