--- lib/pry-doc/pry_ext/show_source_with_c_internals/ruby_source_installer.rb~	2020-03-28 07:37:36.000000000 +0000
+++ lib/pry-doc/pry_ext/show_source_with_c_internals/ruby_source_installer.rb	2021-06-22 16:23:51.614000000 +0000
@@ -32,7 +32,8 @@ module Pry::CInternals
         self.etag_cmd = %{dir /b /s *.c *.h *.y | "#{etag_binary}" - --no-members}
       else
         self.curl_cmd = "curl --fail -L https://github.com/ruby/ruby/archive/v#{ruby_version}.tar.gz | tar xzvf - 2> /dev/null"
-        self.etag_binary = linux? ? File.join(PryDoc.root, "libexec/linux/etags-#{arch}") : "etags"
+        etag_binary = File.join(PryDoc.root, "libexec/linux/etags-#{arch}")
+        self.etag_binary = linux? && File.file?(etag_binary) ? etag_binary : "etags"
         self.etag_cmd = "find . -type f -name '*.[chy]' | #{etag_binary} - --no-members"
       end
     end