diff --git a/news/f2a93c6a-3d20-4662-b510-0a11603837b1.trivial b/news/f2a93c6a-3d20-4662-b510-0a11603837b1.trivial
new file mode 100644
index 000000000..e69de29bb
diff --git a/src/pip/_internal/cli/base_command.py b/src/pip/_internal/cli/base_command.py
index 628faa3ee..5bb8fa2bc 100644
--- a/src/pip/_internal/cli/base_command.py
+++ b/src/pip/_internal/cli/base_command.py
@@ -56,7 +56,7 @@ class Command(CommandContextMixIn):
         super(Command, self).__init__()
         parser_kw = {
             'usage': self.usage,
-            'prog': '%s %s' % (get_prog(), name),
+            'prog': '{} {}'.format(get_prog(), name),
             'formatter': UpdatingDefaultsHelpFormatter(),
             'add_help_option': False,
             'name': name,
@@ -69,7 +69,7 @@ class Command(CommandContextMixIn):
         self.parser = ConfigOptionParser(**parser_kw)
 
         # Commands should add options to this option group
-        optgroup_name = '%s Options' % self.name.capitalize()
+        optgroup_name = '{} Options'.format(self.name.capitalize())
         self.cmd_opts = optparse.OptionGroup(self.parser, optgroup_name)
 
         # Add the general options
diff --git a/src/pip/_internal/cli/cmdoptions.py b/src/pip/_internal/cli/cmdoptions.py
index 42e26951a..f34501990 100644
--- a/src/pip/_internal/cli/cmdoptions.py
+++ b/src/pip/_internal/cli/cmdoptions.py
@@ -851,12 +851,12 @@ def _handle_merge_hash(option, opt_str, value, parser):
     try:
         algo, digest = value.split(':', 1)
     except ValueError:
-        parser.error('Arguments to %s must be a hash name '
-                     'followed by a value, like --hash=sha256:abcde...' %
-                     opt_str)
+        parser.error('Arguments to {} must be a hash name '
+                     'followed by a value, like --hash=sha256:'
+                     'abcde...'.format(opt_str))
     if algo not in STRONG_HASHES:
-        parser.error('Allowed hash algorithms for %s are %s.' %
-                     (opt_str, ', '.join(STRONG_HASHES)))
+        parser.error('Allowed hash algorithms for {} are {}.'.format(
+                     opt_str, ', '.join(STRONG_HASHES)))
     parser.values.hashes.setdefault(algo, []).append(digest)
 
 
diff --git a/src/pip/_internal/cli/main.py b/src/pip/_internal/cli/main.py
index 5e97a5103..172f30dd5 100644
--- a/src/pip/_internal/cli/main.py
+++ b/src/pip/_internal/cli/main.py
@@ -59,7 +59,7 @@ def main(args=None):
     try:
         cmd_name, cmd_args = parse_command(args)
     except PipError as exc:
-        sys.stderr.write("ERROR: %s" % exc)
+        sys.stderr.write("ERROR: {}".format(exc))
         sys.stderr.write(os.linesep)
         sys.exit(1)
 
diff --git a/src/pip/_internal/cli/main_parser.py b/src/pip/_internal/cli/main_parser.py
index a89821d44..4871956c9 100644
--- a/src/pip/_internal/cli/main_parser.py
+++ b/src/pip/_internal/cli/main_parser.py
@@ -86,9 +86,9 @@ def parse_command(args):
     if cmd_name not in commands_dict:
         guess = get_similar_commands(cmd_name)
 
-        msg = ['unknown command "%s"' % cmd_name]
+        msg = ['unknown command "{}"'.format(cmd_name)]
         if guess:
-            msg.append('maybe you meant "%s"' % guess)
+            msg.append('maybe you meant "{}"'.format(guess))
 
         raise CommandError(' - '.join(msg))
 
diff --git a/src/pip/_internal/cli/parser.py b/src/pip/_internal/cli/parser.py
index c99456bae..e799215be 100644
--- a/src/pip/_internal/cli/parser.py
+++ b/src/pip/_internal/cli/parser.py
@@ -33,7 +33,7 @@ class PrettyHelpFormatter(optparse.IndentedHelpFormatter):
     def format_option_strings(self, option):
         return self._format_option_strings(option, ' <%s>', ', ')
 
-    def _format_option_strings(self, option, mvarfmt=' <%s>', optsep=', '):
+    def _format_option_strings(self, option, mvarfmt=' <{}>', optsep=', '):
         """
         Return a comma-separated list of option strings and metavars.
 
@@ -52,7 +52,7 @@ class PrettyHelpFormatter(optparse.IndentedHelpFormatter):
 
         if option.takes_value():
             metavar = option.metavar or option.dest.lower()
-            opts.append(mvarfmt % metavar.lower())
+            opts.append(mvarfmt.format(metavar.lower()))
 
         return ''.join(opts)
 
@@ -66,7 +66,8 @@ class PrettyHelpFormatter(optparse.IndentedHelpFormatter):
         Ensure there is only one newline between usage and the first heading
         if there is no description.
         """
-        msg = '\nUsage: %s\n' % self.indent_lines(textwrap.dedent(usage), "  ")
+        msg = '\nUsage: {}\n'.format(
+            self.indent_lines(textwrap.dedent(usage), "  "))
         return msg
 
     def format_description(self, description):
@@ -82,7 +83,7 @@ class PrettyHelpFormatter(optparse.IndentedHelpFormatter):
             description = description.rstrip()
             # dedent, then reindent
             description = self.indent_lines(textwrap.dedent(description), "  ")
-            description = '%s:\n%s\n' % (label, description)
+            description = '{}:\n{}\n'.format(label, description)
             return description
         else:
             return ''
@@ -150,7 +151,7 @@ class ConfigOptionParser(CustomOptionParser):
         try:
             return option.check_value(key, val)
         except optparse.OptionValueError as exc:
-            print("An error occurred during configuration: %s" % exc)
+            print("An error occurred during configuration: {}".format(exc))
             sys.exit(3)
 
     def _get_ordered_configuration_items(self):
@@ -249,7 +250,7 @@ class ConfigOptionParser(CustomOptionParser):
 
     def error(self, msg):
         self.print_usage(sys.stderr)
-        self.exit(UNKNOWN_ERROR, "%s\n" % msg)
+        self.exit(UNKNOWN_ERROR, "{}\n".format(msg))
 
 
 def invalid_config_error_message(action, key, val):
diff --git a/src/pip/_internal/commands/completion.py b/src/pip/_internal/commands/completion.py
index c532806e3..e0b743e54 100644
--- a/src/pip/_internal/commands/completion.py
+++ b/src/pip/_internal/commands/completion.py
@@ -92,5 +92,5 @@ class CompletionCommand(Command):
             print(BASE_COMPLETION % {'script': script, 'shell': options.shell})
         else:
             sys.stderr.write(
-                'ERROR: You must pass %s\n' % ' or '.join(shell_options)
+                'ERROR: You must pass {}\n' .format(' or '.join(shell_options))
             )
diff --git a/src/pip/_internal/commands/freeze.py b/src/pip/_internal/commands/freeze.py
index c59eb3960..41fea20ca 100644
--- a/src/pip/_internal/commands/freeze.py
+++ b/src/pip/_internal/commands/freeze.py
@@ -65,7 +65,7 @@ class FreezeCommand(Command):
             dest='freeze_all',
             action='store_true',
             help='Do not skip these packages in the output:'
-                 ' %s' % ', '.join(DEV_PKGS))
+                 ' {}'.format(', '.join(DEV_PKGS)))
         self.cmd_opts.add_option(
             '--exclude-editable',
             dest='exclude_editable',
diff --git a/src/pip/_internal/commands/hash.py b/src/pip/_internal/commands/hash.py
index 1dc7fb0ea..f26686156 100644
--- a/src/pip/_internal/commands/hash.py
+++ b/src/pip/_internal/commands/hash.py
@@ -34,8 +34,8 @@ class HashCommand(Command):
             choices=STRONG_HASHES,
             action='store',
             default=FAVORITE_HASH,
-            help='The hash algorithm to use: one of %s' %
-                 ', '.join(STRONG_HASHES))
+            help='The hash algorithm to use: one of {}'.format(
+                 ', '.join(STRONG_HASHES)))
         self.parser.insert_option_group(0, self.cmd_opts)
 
     def run(self, options, args):
diff --git a/src/pip/_internal/commands/help.py b/src/pip/_internal/commands/help.py
index 75af999b4..c17d7a457 100644
--- a/src/pip/_internal/commands/help.py
+++ b/src/pip/_internal/commands/help.py
@@ -29,9 +29,9 @@ class HelpCommand(Command):
         if cmd_name not in commands_dict:
             guess = get_similar_commands(cmd_name)
 
-            msg = ['unknown command "%s"' % cmd_name]
+            msg = ['unknown command "{}"'.format(cmd_name)]
             if guess:
-                msg.append('maybe you meant "%s"' % guess)
+                msg.append('maybe you meant "{}"'.format(guess))
 
             raise CommandError(' - '.join(msg))
 
diff --git a/src/pip/_internal/exceptions.py b/src/pip/_internal/exceptions.py
index dddec789e..882529dec 100644
--- a/src/pip/_internal/exceptions.py
+++ b/src/pip/_internal/exceptions.py
@@ -255,8 +255,8 @@ class HashMismatch(HashError):
         self.gots = gots
 
     def body(self):
-        return '    %s:\n%s' % (self._requirement_name(),
-                                self._hash_comparison())
+        return '    {}:\n{}'.format(self._requirement_name(),
+                                    self._hash_comparison())
 
     def _hash_comparison(self):
         """
@@ -277,10 +277,10 @@ class HashMismatch(HashError):
         lines = []
         for hash_name, expecteds in iteritems(self.allowed):
             prefix = hash_then_or(hash_name)
-            lines.extend(('        Expected %s %s' % (next(prefix), e))
+            lines.extend(('        Expected {} {}'.format(next(prefix), e))
                          for e in expecteds)
-            lines.append('             Got        %s\n' %
-                         self.gots[hash_name].hexdigest())
+            lines.append('             Got        {}\n'.format(
+                         self.gots[hash_name].hexdigest()))
         return '\n'.join(lines)
 
 
diff --git a/src/pip/_internal/index/collector.py b/src/pip/_internal/index/collector.py
index 833079317..69bf738e5 100644
--- a/src/pip/_internal/index/collector.py
+++ b/src/pip/_internal/index/collector.py
@@ -354,7 +354,7 @@ def _get_html_page(link, session=None):
         reason += str(exc)
         _handle_get_page_fail(link, reason, meth=logger.info)
     except requests.ConnectionError as exc:
-        _handle_get_page_fail(link, "connection error: %s" % exc)
+        _handle_get_page_fail(link, "connection error: {}".format(exc))
     except requests.Timeout:
         _handle_get_page_fail(link, "timed out")
     else:
diff --git a/src/pip/_internal/index/package_finder.py b/src/pip/_internal/index/package_finder.py
index a74d78db5..e88ad9f5c 100644
--- a/src/pip/_internal/index/package_finder.py
+++ b/src/pip/_internal/index/package_finder.py
@@ -177,9 +177,10 @@ class LinkEvaluator(object):
             if not ext:
                 return (False, 'not a file')
             if ext not in SUPPORTED_EXTENSIONS:
-                return (False, 'unsupported archive format: %s' % ext)
+                return (False, 'unsupported archive format: {}'.format(ext))
             if "binary" not in self._formats and ext == WHEEL_EXTENSION:
-                reason = 'No binaries permitted for %s' % self.project_name
+                reason = 'No binaries permitted for {}'.format(
+                    self.project_name)
                 return (False, reason)
             if "macosx10" in link.path and ext == '.zip':
                 return (False, 'macosx10 one')
@@ -189,7 +190,8 @@ class LinkEvaluator(object):
                 except InvalidWheelFilename:
                     return (False, 'invalid wheel filename')
                 if canonicalize_name(wheel.name) != self._canonical_name:
-                    reason = 'wrong project name (not %s)' % self.project_name
+                    reason = 'wrong project name (not {})'.format(
+                        self.project_name)
                     return (False, reason)
 
                 supported_tags = self._target_python.get_tags()
@@ -208,16 +210,16 @@ class LinkEvaluator(object):
 
         # This should be up by the self.ok_binary check, but see issue 2700.
         if "source" not in self._formats and ext != WHEEL_EXTENSION:
-            return (False, 'No sources permitted for %s' % self.project_name)
+            reason = 'No sources permitted for {}'.format(self.project_name)
+            return (False, reason)
 
         if not version:
             version = _extract_version_from_fragment(
                 egg_info, self._canonical_name,
             )
         if not version:
-            return (
-                False, 'Missing project version for %s' % self.project_name,
-            )
+            reason = 'Missing project version for {}'.format(self.project_name)
+            return (False, reason)
 
         match = self._py_version_re.search(version)
         if match:
@@ -524,8 +526,8 @@ class CandidateEvaluator(object):
             wheel = Wheel(link.filename)
             if not wheel.supported(valid_tags):
                 raise UnsupportedWheel(
-                    "%s is not a supported wheel for this platform. It "
-                    "can't be sorted." % wheel.filename
+                    "{} is not a supported wheel for this platform. It "
+                    "can't be sorted.".format(wheel.filename)
                 )
             if self._prefer_binary:
                 binary_preference = 1
@@ -924,7 +926,8 @@ class PackageFinder(object):
             )
 
             raise DistributionNotFound(
-                'No matching distribution found for %s' % req
+                'No matching distribution found for {}'.format(
+                    req)
             )
 
         best_installed = False
diff --git a/src/pip/_internal/models/link.py b/src/pip/_internal/models/link.py
index 34fbcbfe7..1b3aa591a 100644
--- a/src/pip/_internal/models/link.py
+++ b/src/pip/_internal/models/link.py
@@ -66,12 +66,12 @@ class Link(KeyBasedCompareMixin):
     def __str__(self):
         # type: () -> str
         if self.requires_python:
-            rp = ' (requires-python:%s)' % self.requires_python
+            rp = ' (requires-python:{})'.format(self.requires_python)
         else:
             rp = ''
         if self.comes_from:
-            return '%s (from %s)%s' % (redact_auth_from_url(self._url),
-                                       self.comes_from, rp)
+            return '{} (from {}){}'.format(
+                redact_auth_from_url(self._url), self.comes_from, rp)
         else:
             return redact_auth_from_url(str(self._url))
 
diff --git a/src/pip/_internal/models/wheel.py b/src/pip/_internal/models/wheel.py
index f1e3f44c5..4d4068f3b 100644
--- a/src/pip/_internal/models/wheel.py
+++ b/src/pip/_internal/models/wheel.py
@@ -30,7 +30,7 @@ class Wheel(object):
         wheel_info = self.wheel_file_re.match(filename)
         if not wheel_info:
             raise InvalidWheelFilename(
-                "%s is not a valid wheel filename." % filename
+                "{} is not a valid wheel filename.".format(filename)
             )
         self.filename = filename
         self.name = wheel_info.group('name').replace('_', '-')
diff --git a/src/pip/_internal/network/auth.py b/src/pip/_internal/network/auth.py
index 1e1da54ca..94da3d46a 100644
--- a/src/pip/_internal/network/auth.py
+++ b/src/pip/_internal/network/auth.py
@@ -215,7 +215,7 @@ class MultiDomainBasicAuth(AuthBase):
 
     # Factored out to allow for easy patching in tests
     def _prompt_for_password(self, netloc):
-        username = ask_input("User for %s: " % netloc)
+        username = ask_input("User for {}: ".format(netloc))
         if not username:
             return None, None
         auth = get_keyring_auth(netloc, username)
diff --git a/src/pip/_internal/operations/build/wheel_legacy.py b/src/pip/_internal/operations/build/wheel_legacy.py
index 3ebd9fe44..96dd09a45 100644
--- a/src/pip/_internal/operations/build/wheel_legacy.py
+++ b/src/pip/_internal/operations/build/wheel_legacy.py
@@ -89,7 +89,7 @@ def build_wheel_legacy(
         destination_dir=tempd,
     )
 
-    spin_message = 'Building wheel for %s (setup.py)' % (name,)
+    spin_message = 'Building wheel for {} (setup.py)'.format(name)
     with open_spinner(spin_message) as spinner:
         logger.debug('Destination directory: %s', tempd)
 
diff --git a/src/pip/_internal/operations/freeze.py b/src/pip/_internal/operations/freeze.py
index 36a5c339a..5575d70d0 100644
--- a/src/pip/_internal/operations/freeze.py
+++ b/src/pip/_internal/operations/freeze.py
@@ -60,7 +60,7 @@ def freeze(
         skip_match = re.compile(skip_regex).search
 
     for link in find_links:
-        yield '-f %s' % link
+        yield '-f {}'.format(link)
     installations = {}  # type: Dict[str, FrozenRequirement]
     for dist in get_installed_distributions(local_only=local_only,
                                             skip=(),
@@ -261,5 +261,5 @@ class FrozenRequirement(object):
     def __str__(self):
         req = self.req
         if self.editable:
-            req = '-e %s' % req
+            req = '-e {}'.format(req)
         return '\n'.join(list(self.comments) + [str(req)]) + '\n'
diff --git a/src/pip/_internal/operations/install/wheel.py b/src/pip/_internal/operations/install/wheel.py
index aac975c3a..b1a76a24c 100644
--- a/src/pip/_internal/operations/install/wheel.py
+++ b/src/pip/_internal/operations/install/wheel.py
@@ -504,11 +504,11 @@ def install_unpacked_wheel(
 
         if os.environ.get("ENSUREPIP_OPTIONS", "") != "altinstall":
             scripts_to_generate.append(
-                'pip%s = %s' % (sys.version_info[0], pip_script)
+                'pip{} = {}'.format(sys.version_info[0], pip_script)
             )
 
         scripts_to_generate.append(
-            'pip%s = %s' % (get_major_minor_version(), pip_script)
+            'pip{} = {}'.format(get_major_minor_version(), pip_script)
         )
         # Delete any other versioned pip entry points
         pip_ep = [k for k in console if re.match(r'pip(\d(\.\d)?)?$', k)]
@@ -522,7 +522,7 @@ def install_unpacked_wheel(
             )
 
         scripts_to_generate.append(
-            'easy_install-%s = %s' % (
+            'easy_install-{} = {}'.format(
                 get_major_minor_version(), easy_install_script
             )
         )
diff --git a/src/pip/_internal/req/__init__.py b/src/pip/_internal/req/__init__.py
index 05e089728..d2d027ade 100644
--- a/src/pip/_internal/req/__init__.py
+++ b/src/pip/_internal/req/__init__.py
@@ -48,18 +48,17 @@ def install_given_reqs(
     """
 
     if to_install:
-        msg = 'Installing collected packages: {}'.format(
-            ', '.join([req.name for req in to_install])
+        logger.info(
+            'Installing collected packages: %s',
+            ', '.join([req.name for req in to_install]),
         )
-        logger.info(msg)
 
     installed = []
 
     with indent_log():
         for requirement in to_install:
             if requirement.should_reinstall:
-                logger.info('Attempting uninstall: {}'.format(
-                    requirement.name))
+                logger.info('Attempting uninstall: %s', requirement.name)
                 with indent_log():
                     uninstalled_pathset = requirement.uninstall(
                         auto_confirm=True
diff --git a/src/pip/_internal/req/constructors.py b/src/pip/_internal/req/constructors.py
index 1f3cd8a10..16f2c9c7d 100644
--- a/src/pip/_internal/req/constructors.py
+++ b/src/pip/_internal/req/constructors.py
@@ -137,16 +137,17 @@ def parse_editable(editable_req):
     vc_type = url.split('+', 1)[0].lower()
 
     if not vcs.get_backend(vc_type):
-        error_message = 'For --editable=%s only ' % editable_req + \
-            ', '.join([backend.name + '+URL' for backend in vcs.backends]) + \
-            ' is currently supported'
+        error_message = 'For --editable={} only '.format(
+            editable_req + ', '.join(
+                [backend.name + '+URL' for backend in vcs.backends]) +
+            ' is currently supported')
         raise InstallationError(error_message)
 
     package_name = Link(url).egg_fragment
     if not package_name:
         raise InstallationError(
-            "Could not detect requirement name for '%s', please specify one "
-            "with #egg=your_package_name" % editable_req
+            "Could not detect requirement name for '{}', please specify one "
+            "with #egg=your_package_name".format(editable_req)
         )
     return package_name, url, None
 
@@ -166,16 +167,18 @@ def deduce_helpful_msg(req):
             with open(req, 'r') as fp:
                 # parse first line only
                 next(parse_requirements(fp.read()))
-                msg += " The argument you provided " + \
-                    "(%s) appears to be a" % (req) + \
-                    " requirements file. If that is the" + \
-                    " case, use the '-r' flag to install" + \
+                msg += (
+                    "The argument you provided "
+                    "({}) appears to be a"
+                    " requirements file. If that is the"
+                    " case, use the '-r' flag to install"
                     " the packages specified within it."
+                ).format(req)
         except RequirementParseError:
             logger.debug("Cannot parse '%s' as requirements \
             file" % (req), exc_info=True)
     else:
-        msg += " File '%s' does not exist." % (req)
+        msg += " File '{}' does not exist.".format(req)
     return msg
 
 
@@ -201,7 +204,7 @@ def parse_req_from_editable(editable_req):
         try:
             req = Requirement(name)
         except InvalidRequirement:
-            raise InstallationError("Invalid requirement: '%s'" % name)
+            raise InstallationError("Invalid requirement: '{}'".format(name))
     else:
         req = None
 
@@ -415,7 +418,7 @@ def install_req_from_req_string(
     try:
         req = Requirement(req_string)
     except InvalidRequirement:
-        raise InstallationError("Invalid requirement: '%s'" % req_string)
+        raise InstallationError("Invalid requirement: '{}'".format(req_string))
 
     domains_not_allowed = [
         PyPI.file_storage_domain,
@@ -427,7 +430,7 @@ def install_req_from_req_string(
         raise InstallationError(
             "Packages installed from PyPI cannot depend on packages "
             "which are not also hosted on PyPI.\n"
-            "%s depends on %s " % (comes_from.name, req)
+            "{} depends on {} ".format(comes_from.name, req)
         )
 
     return InstallRequirement(
diff --git a/src/pip/_internal/req/req_file.py b/src/pip/_internal/req/req_file.py
index 8c7810481..baf8d03ea 100644
--- a/src/pip/_internal/req/req_file.py
+++ b/src/pip/_internal/req/req_file.py
@@ -183,7 +183,7 @@ def handle_line(
     """
 
     # preserve for the nested code path
-    line_comes_from = '%s %s (line %s)' % (
+    line_comes_from = '{} {} (line {})'.format(
         '-c' if line.constraint else '-r', line.filename, line.lineno,
     )
 
@@ -329,7 +329,7 @@ class RequirementsFileParser(object):
                 args_str, opts = self._line_parser(line)
             except OptionParsingError as e:
                 # add offending line
-                msg = 'Invalid requirement: %s\n%s' % (line, e.msg)
+                msg = 'Invalid requirement: {}\n{}'.format(line, e.msg)
                 raise RequirementsFileParseError(msg)
 
             yield ParsedLine(
@@ -520,8 +520,9 @@ def get_file_content(url, session, comes_from=None):
     elif scheme == 'file':
         if comes_from and comes_from.startswith('http'):
             raise InstallationError(
-                'Requirements file %s references URL %s, which is local'
-                % (comes_from, url))
+                'Requirements file {} references URL {}, '
+                'which is local'.format(comes_from, url)
+            )
 
         path = url.split(':', 1)[1]
         path = path.replace('\\', '/')
@@ -538,7 +539,7 @@ def get_file_content(url, session, comes_from=None):
             content = auto_decode(f.read())
     except IOError as exc:
         raise InstallationError(
-            'Could not open requirements file: %s' % str(exc)
+            'Could not open requirements file: {}'.format(exc)
         )
     return url, content
 
diff --git a/src/pip/_internal/req/req_install.py b/src/pip/_internal/req/req_install.py
index 6bbad8857..e560cf449 100644
--- a/src/pip/_internal/req/req_install.py
+++ b/src/pip/_internal/req/req_install.py
@@ -195,25 +195,25 @@ class InstallRequirement(object):
         if self.req:
             s = str(self.req)
             if self.link:
-                s += ' from %s' % redact_auth_from_url(self.link.url)
+                s += ' from {}'.format(redact_auth_from_url(self.link.url))
         elif self.link:
             s = redact_auth_from_url(self.link.url)
         else:
             s = '<InstallRequirement>'
         if self.satisfied_by is not None:
-            s += ' in %s' % display_path(self.satisfied_by.location)
+            s += ' in {}'.format(display_path(self.satisfied_by.location))
         if self.comes_from:
             if isinstance(self.comes_from, six.string_types):
                 comes_from = self.comes_from  # type: Optional[str]
             else:
                 comes_from = self.comes_from.from_path()
             if comes_from:
-                s += ' (from %s)' % comes_from
+                s += ' (from {})'.format(comes_from)
         return s
 
     def __repr__(self):
         # type: () -> str
-        return '<%s object: %s editable=%r>' % (
+        return '<{} object: {} editable={!r}>'.format(
             self.__class__.__name__, str(self), self.editable)
 
     def format_debug(self):
@@ -452,8 +452,8 @@ class InstallRequirement(object):
                         dist_in_site_packages(existing_dist)):
                     raise InstallationError(
                         "Will not install to the user site because it will "
-                        "lack sys.path precedence to %s in %s" %
-                        (existing_dist.project_name, existing_dist.location)
+                        "lack sys.path precedence to {} in {}".format(
+                            existing_dist.project_name, existing_dist.location)
                     )
             else:
                 self.should_reinstall = True
@@ -483,7 +483,7 @@ class InstallRequirement(object):
     @property
     def setup_py_path(self):
         # type: () -> str
-        assert self.source_dir, "No source dir for %s" % self
+        assert self.source_dir, "No source dir for {}".format(self)
         setup_py = os.path.join(self.unpacked_source_directory, 'setup.py')
 
         # Python2 __file__ should not be unicode
@@ -495,7 +495,7 @@ class InstallRequirement(object):
     @property
     def pyproject_toml_path(self):
         # type: () -> str
-        assert self.source_dir, "No source dir for %s" % self
+        assert self.source_dir, "No source dir for {}".format(self)
         return make_pyproject_path(self.unpacked_source_directory)
 
     def load_pyproject_toml(self):
@@ -654,8 +654,8 @@ class InstallRequirement(object):
                 vcs_backend.export(self.source_dir, url=hidden_url)
         else:
             assert 0, (
-                'Unexpected version control type (in %s): %s'
-                % (self.link, vc_type))
+                'Unexpected version control type (in {}): {}'.format(
+                    self.link, vc_type))
 
     # Top-level Actions
     def uninstall(self, auto_confirm=False, verbose=False):
@@ -710,13 +710,15 @@ class InstallRequirement(object):
         assert self.source_dir
 
         create_archive = True
-        archive_name = '%s-%s.zip' % (self.name, self.metadata["version"])
+        archive_name = '{}-{}.zip'.format(self.name, self.metadata["version"])
         archive_path = os.path.join(build_dir, archive_name)
 
         if os.path.exists(archive_path):
             response = ask_path_exists(
-                'The file %s exists. (i)gnore, (w)ipe, (b)ackup, (a)bort ' %
-                display_path(archive_path), ('i', 'w', 'b', 'a'))
+                'The file {} exists. (i)gnore, (w)ipe, '
+                '(b)ackup, (a)bort '.format(
+                    display_path(archive_path)),
+                ('i', 'w', 'b', 'a'))
             if response == 'i':
                 create_archive = False
             elif response == 'w':
diff --git a/src/pip/_internal/req/req_set.py b/src/pip/_internal/req/req_set.py
index 087ac5925..1312622b8 100644
--- a/src/pip/_internal/req/req_set.py
+++ b/src/pip/_internal/req/req_set.py
@@ -108,8 +108,8 @@ class RequirementSet(object):
             tags = pep425tags.get_supported()
             if (self.check_supported_wheels and not wheel.supported(tags)):
                 raise InstallationError(
-                    "%s is not a supported wheel on this platform." %
-                    wheel.filename
+                    "{} is not a supported wheel on this platform.".format(
+                        wheel.filename)
                 )
 
         # This next bit is really a sanity check.
@@ -138,8 +138,8 @@ class RequirementSet(object):
         )
         if has_conflicting_requirement:
             raise InstallationError(
-                "Double requirement given: %s (already in %s, name=%r)"
-                % (install_req, existing_req, install_req.name)
+                "Double requirement given: {} (already in {}, name={!r})"
+                .format(install_req, existing_req, install_req.name)
             )
 
         # When no existing requirement exists, add the requirement as a
@@ -164,9 +164,9 @@ class RequirementSet(object):
         if does_not_satisfy_constraint:
             self.reqs_to_cleanup.append(install_req)
             raise InstallationError(
-                "Could not satisfy constraints for '%s': "
+                "Could not satisfy constraints for '{}': "
                 "installation from path or url cannot be "
-                "constrained to a version" % install_req.name,
+                "constrained to a version".format(install_req.name)
             )
         # If we're now installing a constraint, mark the existing
         # object for real installation.
diff --git a/src/pip/_internal/req/req_tracker.py b/src/pip/_internal/req/req_tracker.py
index d72a41d20..14adeab29 100644
--- a/src/pip/_internal/req/req_tracker.py
+++ b/src/pip/_internal/req/req_tracker.py
@@ -60,7 +60,7 @@ def get_requirement_tracker():
                 TempDirectory(kind='req-tracker')
             ).path
             ctx.enter_context(update_env_context_manager(PIP_REQ_TRACKER=root))
-            logger.debug("Initialized build tracking at {}".format(root))
+            logger.debug("Initialized build tracking at %s", root)
 
         with RequirementTracker(root) as tracker:
             yield tracker
@@ -111,7 +111,8 @@ class RequirementTracker(object):
             if e.errno != errno.ENOENT:
                 raise
         else:
-            message = '%s is already being built: %s' % (req.link, contents)
+            message = '{} is already being built: {}'.format(
+                req.link, contents)
             raise LookupError(message)
 
         # If we're here, req should really not be building already.
diff --git a/src/pip/_internal/req/req_uninstall.py b/src/pip/_internal/req/req_uninstall.py
index 5971b130e..ec9da2c34 100644
--- a/src/pip/_internal/req/req_uninstall.py
+++ b/src/pip/_internal/req/req_uninstall.py
@@ -540,8 +540,9 @@ class UninstallPathSet(object):
             with open(develop_egg_link, 'r') as fh:
                 link_pointer = os.path.normcase(fh.readline().strip())
             assert (link_pointer == dist.location), (
-                'Egg-link %s does not match installed location of %s '
-                '(at %s)' % (link_pointer, dist.project_name, dist.location)
+                'Egg-link {} does not match installed location of {} '
+                '(at {})'.format(
+                    link_pointer, dist.project_name, dist.location)
             )
             paths_to_remove.add(develop_egg_link)
             easy_install_pth = os.path.join(os.path.dirname(develop_egg_link),
@@ -586,7 +587,8 @@ class UninstallPthEntries(object):
         # type: (str) -> None
         if not os.path.isfile(pth_file):
             raise UninstallationError(
-                "Cannot remove entries from nonexistent file %s" % pth_file
+                "Cannot remove entries from nonexistent file {}".format(
+                    pth_file)
             )
         self.file = pth_file
         self.entries = set()  # type: Set[str]
diff --git a/src/pip/_internal/utils/compat.py b/src/pip/_internal/utils/compat.py
index 6efa52ad2..08c292d18 100644
--- a/src/pip/_internal/utils/compat.py
+++ b/src/pip/_internal/utils/compat.py
@@ -184,7 +184,8 @@ def get_path_uid(path):
         else:
             # raise OSError for parity with os.O_NOFOLLOW above
             raise OSError(
-                "%s is a symlink; Will not return uid for symlinks" % path
+                "{} is a symlink; Will not return uid for symlinks".format(
+                    path)
             )
     return file_uid
 
diff --git a/src/pip/_internal/utils/hashes.py b/src/pip/_internal/utils/hashes.py
index 4c41551a2..396cf82e7 100644
--- a/src/pip/_internal/utils/hashes.py
+++ b/src/pip/_internal/utils/hashes.py
@@ -73,7 +73,9 @@ class Hashes(object):
             try:
                 gots[hash_name] = hashlib.new(hash_name)
             except (ValueError, TypeError):
-                raise InstallationError('Unknown hash name: %s' % hash_name)
+                raise InstallationError(
+                    'Unknown hash name: {}'.format(hash_name)
+                )
 
         for chunk in chunks:
             for hash in itervalues(gots):
diff --git a/src/pip/_internal/utils/misc.py b/src/pip/_internal/utils/misc.py
index 4a5816019..667ed80a3 100644
--- a/src/pip/_internal/utils/misc.py
+++ b/src/pip/_internal/utils/misc.py
@@ -120,7 +120,7 @@ def get_prog():
     try:
         prog = os.path.basename(sys.argv[0])
         if prog in ('__main__.py', '-c'):
-            return "%s -m pip" % sys.executable
+            return "{} -m pip".format(sys.executable)
         else:
             return prog
     except (AttributeError, TypeError, IndexError):
@@ -228,8 +228,8 @@ def _check_no_input(message):
     """Raise an error if no input is allowed."""
     if os.environ.get('PIP_NO_INPUT'):
         raise Exception(
-            'No input was expected ($PIP_NO_INPUT set); question: %s' %
-            message
+            'No input was expected ($PIP_NO_INPUT set); question: {}'.format(
+                message)
         )
 
 
@@ -242,8 +242,8 @@ def ask(message, options):
         response = response.strip().lower()
         if response not in options:
             print(
-                'Your response (%r) was not one of the expected responses: '
-                '%s' % (response, ', '.join(options))
+                'Your response ({!r}) was not one of the expected responses: '
+                '{}'.format(response, ', '.join(options))
             )
         else:
             return response
diff --git a/src/pip/_internal/utils/subprocess.py b/src/pip/_internal/utils/subprocess.py
index ea0176d34..61c40a49e 100644
--- a/src/pip/_internal/utils/subprocess.py
+++ b/src/pip/_internal/utils/subprocess.py
@@ -242,14 +242,14 @@ def call_subprocess(
             raise InstallationError(exc_msg)
         elif on_returncode == 'warn':
             subprocess_logger.warning(
-                'Command "%s" had error code %s in %s',
-                command_desc, proc.returncode, cwd,
+                'Command "{}" had error code {} in {}'.format(
+                    command_desc, proc.returncode, cwd)
             )
         elif on_returncode == 'ignore':
             pass
         else:
-            raise ValueError('Invalid value: on_returncode=%s' %
-                             repr(on_returncode))
+            raise ValueError('Invalid value: on_returncode={!r}'.format(
+                             on_returncode))
     return ''.join(all_output)
 
 
diff --git a/src/pip/_internal/utils/ui.py b/src/pip/_internal/utils/ui.py
index 87782aa64..f84feb317 100644
--- a/src/pip/_internal/utils/ui.py
+++ b/src/pip/_internal/utils/ui.py
@@ -153,7 +153,7 @@ class DownloadProgressMixin(object):
     @property
     def pretty_eta(self):
         if self.eta:
-            return "eta %s" % self.eta_td
+            return "eta {}".format(self.eta_td)
         return ""
 
     def iter(self, it):
@@ -399,7 +399,7 @@ class NonInteractiveSpinner(SpinnerInterface):
         # type: (str) -> None
         if self._finished:
             return
-        self._update("finished with status '%s'" % (final_status,))
+        self._update("finished with status '{}'".format(final_status))
         self._finished = True
 
 
diff --git a/src/pip/_internal/utils/wheel.py b/src/pip/_internal/utils/wheel.py
index 837e0afd7..e4166a68e 100644
--- a/src/pip/_internal/utils/wheel.py
+++ b/src/pip/_internal/utils/wheel.py
@@ -215,8 +215,8 @@ def check_compatibility(version, name):
     """
     if version[0] > VERSION_COMPATIBLE[0]:
         raise UnsupportedWheel(
-            "%s's Wheel-Version (%s) is not compatible with this version "
-            "of pip" % (name, '.'.join(map(str, version)))
+            "{}'s Wheel-Version ({}) is not compatible with this version "
+            "of pip".format(name, '.'.join(map(str, version)))
         )
     elif version > VERSION_COMPATIBLE:
         logger.warning(
diff --git a/src/pip/_internal/vcs/versioncontrol.py b/src/pip/_internal/vcs/versioncontrol.py
index 7cfd56882..1ec986ba5 100644
--- a/src/pip/_internal/vcs/versioncontrol.py
+++ b/src/pip/_internal/vcs/versioncontrol.py
@@ -574,7 +574,8 @@ class VersionControl(object):
             self.name,
             url,
         )
-        response = ask_path_exists('What to do?  %s' % prompt[0], prompt[1])
+        response = ask_path_exists('What to do?  {}'.format(
+            prompt[0]), prompt[1])
 
         if response == 'a':
             sys.exit(-1)