diff --git a/lib/redmine/diff_table.rb b/lib/redmine/diff_table.rb
index 2976d2228..418d6395a 100644
--- a/lib/redmine/diff_table.rb
+++ b/lib/redmine/diff_table.rb
@@ -118,7 +118,7 @@ module Redmine
     end
 
     def parse_line(line, type="inline")
-      if line[0, 1] == "+"
+      if line.start_with?('+')
         diff = diff_for_added_line
         diff.line_right = line[1..-1]
         diff.nb_line_right = @line_num_r
@@ -126,7 +126,7 @@ module Redmine
         @line_num_r += 1
         @added += 1
         true
-      elsif line[0, 1] == "-"
+      elsif line.start_with?('-')
         diff = Diff.new
         diff.line_left = line[1..-1]
         diff.nb_line_left = @line_num_l
@@ -137,7 +137,7 @@ module Redmine
         true
       else
         write_offsets
-        if /\s/.match?(line[0, 1])
+        if line.start_with?(/\s/)
           diff = Diff.new
           diff.line_right = line[1..-1]
           diff.nb_line_right = @line_num_r
@@ -187,4 +187,4 @@ module Redmine
       end
     end
   end
-end
+end
\ No newline at end of file
diff --git a/lib/redmine/export/pdf.rb b/lib/redmine/export/pdf.rb
index e586a2a0a..cdf8eca3c 100644
--- a/lib/redmine/export/pdf.rb
+++ b/lib/redmine/export/pdf.rb
@@ -120,7 +120,7 @@ module Redmine
         end
 
         def get_sever_url(url)
-          if !empty_string(url) and (url[0, 1] == '/')
+          if !empty_string(url) and url.start_with?('/')
             Setting.host_name.split('/')[0] + url
           else
             url
diff --git a/lib/redmine/scm/adapters/abstract_adapter.rb b/lib/redmine/scm/adapters/abstract_adapter.rb
index 5d92bb2d7..0ad3d7f45 100644
--- a/lib/redmine/scm/adapters/abstract_adapter.rb
+++ b/lib/redmine/scm/adapters/abstract_adapter.rb
@@ -158,12 +158,12 @@ module Redmine
 
         def with_leading_slash(path)
           path ||= ''
-          (path[0, 1]!="/") ? "/#{path}" : path
+          path.start_with?('/') ? path : "/#{path}"
         end
 
         def with_trailling_slash(path)
           path ||= ''
-          (path[-1, 1] == "/") ? path : "#{path}/"
+          path.end_with?('/') ? path : "#{path}/"
         end
 
         def without_leading_slash(path)
@@ -173,7 +173,7 @@ module Redmine
 
         def without_trailling_slash(path)
           path ||= ''
-          (path[-1, 1] == "/") ? path[0..-2] : path
+          path.end_with?('/') ? path[0..-2] : path
         end
 
         def valid_name?(name)