diff --git a/bin/bundle b/bin/bundle
index 59dad21c60..1a0b06b005 100755
--- a/bin/bundle
+++ b/bin/bundle
@@ -10,11 +10,11 @@ require 'rubygems'
 
 version = ">= 0.a"
 
-if ARGV.first
-  str = ARGV.first
-  str = str.dup.force_encoding("BINARY") if str.respond_to? :force_encoding
-  if str =~ /\A_(.*)_\z/ and Gem::Version.correct?($1) then
-    version = $1
+str = ARGV.first
+if str
+  str = str.b[/\A_(.*)_\z/, 1]
+  if str and Gem::Version.correct?(str)
+    version = str
     ARGV.shift
   end
 end
diff --git a/bin/bundler b/bin/bundler
index 7ef736899d..e15eb39ed7 100755
--- a/bin/bundler
+++ b/bin/bundler
@@ -10,11 +10,11 @@ require 'rubygems'
 
 version = ">= 0.a"
 
-if ARGV.first
-  str = ARGV.first
-  str = str.dup.force_encoding("BINARY") if str.respond_to? :force_encoding
-  if str =~ /\A_(.*)_\z/ and Gem::Version.correct?($1) then
-    version = $1
+str = ARGV.first
+if str
+  str = str.b[/\A_(.*)_\z/, 1]
+  if str and Gem::Version.correct?(str)
+    version = str
     ARGV.shift
   end
 end
diff --git a/bin/irb b/bin/irb
index e44609a1b0..ae6d358c9d 100755
--- a/bin/irb
+++ b/bin/irb
@@ -10,11 +10,11 @@ require 'rubygems'
 
 version = ">= 0.a"
 
-if ARGV.first
-  str = ARGV.first
-  str = str.dup.force_encoding("BINARY") if str.respond_to? :force_encoding
-  if str =~ /\A_(.*)_\z/ and Gem::Version.correct?($1) then
-    version = $1
+str = ARGV.first
+if str
+  str = str.b[/\A_(.*)_\z/, 1]
+  if str and Gem::Version.correct?(str)
+    version = str
     ARGV.shift
   end
 end
diff --git a/bin/rdoc b/bin/rdoc
index 74e8b025b4..8fa948cddb 100755
--- a/bin/rdoc
+++ b/bin/rdoc
@@ -10,11 +10,11 @@ require 'rubygems'
 
 version = ">= 0.a"
 
-if ARGV.first
-  str = ARGV.first
-  str = str.dup.force_encoding("BINARY") if str.respond_to? :force_encoding
-  if str =~ /\A_(.*)_\z/ and Gem::Version.correct?($1) then
-    version = $1
+str = ARGV.first
+if str
+  str = str.b[/\A_(.*)_\z/, 1]
+  if str and Gem::Version.correct?(str)
+    version = str
     ARGV.shift
   end
 end
diff --git a/bin/ri b/bin/ri
index eaca302681..0cc2f73bb6 100755
--- a/bin/ri
+++ b/bin/ri
@@ -10,11 +10,11 @@ require 'rubygems'
 
 version = ">= 0.a"
 
-if ARGV.first
-  str = ARGV.first
-  str = str.dup.force_encoding("BINARY") if str.respond_to? :force_encoding
-  if str =~ /\A_(.*)_\z/ and Gem::Version.correct?($1) then
-    version = $1
+str = ARGV.first
+if str
+  str = str.b[/\A_(.*)_\z/, 1]
+  if str and Gem::Version.correct?(str)
+    version = str
     ARGV.shift
   end
 end