diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index b29ba4260c..fb922265c4 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -58,7 +58,7 @@ repos:
       # auto format Python codes within docstrings
       - id: blacken-docs
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.4.1
+    rev: v0.4.2
     hooks:
       # lint & attempt to correct failures (e.g. pyupgrade)
       - id: ruff
diff --git a/conda_build/_link.py b/conda_build/_link.py
index af841c0275..e8984fcd37 100644
--- a/conda_build/_link.py
+++ b/conda_build/_link.py
@@ -26,7 +26,7 @@
     SITE_PACKAGES = "Lib/site-packages"
 else:
     BIN_DIR = join(PREFIX, "bin")
-    SITE_PACKAGES = "lib/python%s/site-packages" % sys.version[:3]
+    SITE_PACKAGES = f"lib/python{sys.version[:3]}/site-packages"
 
 # the list of these files is going to be store in info/_files
 FILES = []
@@ -110,20 +110,20 @@ def create_script(fn):
     dst = join(BIN_DIR, fn)
     if sys.platform == "win32":
         shutil.copy2(src, dst + "-script.py")
-        FILES.append("Scripts/%s-script.py" % fn)
+        FILES.append(f"Scripts/{fn}-script.py")
         shutil.copy2(
             join(THIS_DIR, "cli-%d.exe" % (8 * tuple.__itemsize__)), dst + ".exe"
         )
-        FILES.append("Scripts/%s.exe" % fn)
+        FILES.append(f"Scripts/{fn}.exe")
     else:
         with open(src) as fi:
             data = fi.read()
         with open(dst, "w") as fo:
-            shebang = replace_long_shebang("#!%s\n" % normpath(sys.executable))
+            shebang = replace_long_shebang(f"#!{normpath(sys.executable)}\n")
             fo.write(shebang)
             fo.write(data)
         os.chmod(dst, 0o775)
-        FILES.append("bin/%s" % fn)
+        FILES.append(f"bin/{fn}")
 
 
 def create_scripts(files):
@@ -140,9 +140,9 @@ def main():
     link_files("site-packages", SITE_PACKAGES, DATA["site-packages"])
     link_files("Examples", "Examples", DATA["Examples"])
 
-    with open(join(PREFIX, "conda-meta", "%s.files" % DATA["dist"]), "w") as fo:
+    with open(join(PREFIX, "conda-meta", "{}.files".format(DATA["dist"])), "w") as fo:
         for f in FILES:
-            fo.write("%s\n" % f)
+            fo.write(f"{f}\n")
 
 
 if __name__ == "__main__":
diff --git a/conda_build/api.py b/conda_build/api.py
index 571f08f534..cc866a865d 100644
--- a/conda_build/api.py
+++ b/conda_build/api.py
@@ -418,7 +418,7 @@ def convert(
             "Conversion from wheel packages is not implemented yet, stay tuned."
         )
     else:
-        raise RuntimeError("cannot convert: %s" % package_file)
+        raise RuntimeError(f"cannot convert: {package_file}")
 
 
 def test_installable(channel: str = "defaults") -> bool:
diff --git a/conda_build/build.py b/conda_build/build.py
index f1bf8eec02..6dd2b49256 100644
--- a/conda_build/build.py
+++ b/conda_build/build.py
@@ -774,7 +774,7 @@ def copy_readme(m):
     if readme:
         src = join(m.config.work_dir, readme)
         if not isfile(src):
-            sys.exit("Error: no readme file: %s" % readme)
+            sys.exit(f"Error: no readme file: {readme}")
         dst = join(m.config.info_dir, readme)
         utils.copy_into(src, dst, m.config.timeout, locking=m.config.locking)
         if os.path.split(readme)[1] not in {"README.md", "README.rst", "README"}:
@@ -1187,7 +1187,7 @@ def record_prefix_files(m, files_with_prefix):
                     if fn in text_has_prefix_files:
                         text_has_prefix_files.remove(fn)
                 else:
-                    ignored_because = " (not in build/%s_has_prefix_files)" % (mode)
+                    ignored_because = f" (not in build/{mode}_has_prefix_files)"
 
                 print(
                     "{fn} ({mode}): {action}{reason}".format(
@@ -1204,10 +1204,10 @@ def record_prefix_files(m, files_with_prefix):
     # make sure we found all of the files expected
     errstr = ""
     for f in text_has_prefix_files:
-        errstr += "Did not detect hard-coded path in %s from has_prefix_files\n" % f
+        errstr += f"Did not detect hard-coded path in {f} from has_prefix_files\n"
     for f in binary_has_prefix_files:
         errstr += (
-            "Did not detect hard-coded path in %s from binary_has_prefix_files\n" % f
+            f"Did not detect hard-coded path in {f} from binary_has_prefix_files\n"
         )
     if errstr:
         raise RuntimeError(errstr)
@@ -1276,7 +1276,7 @@ def write_about_json(m):
     with open(join(m.config.info_dir, "about.json"), "w") as fo:
         d = {}
         for key, default in FIELDS["about"].items():
-            value = m.get_value("about/%s" % key)
+            value = m.get_value(f"about/{key}")
             if value:
                 d[key] = value
             if default is list:
@@ -1332,7 +1332,7 @@ def write_info_json(m: MetaData):
                 "# $ conda create --name <env> --file <this file>"
             )
             for dist in sorted(runtime_deps + [" ".join(m.dist().rsplit("-", 2))]):
-                fo.write("%s\n" % "=".join(dist.split()))
+                fo.write("{}\n".format("=".join(dist.split())))
 
     mode_dict = {"mode": "w", "encoding": "utf-8"}
     with open(join(m.config.info_dir, "index.json"), **mode_dict) as fo:
@@ -1355,10 +1355,10 @@ def get_entry_point_script_names(entry_point_scripts):
     for entry_point in entry_point_scripts:
         cmd = entry_point[: entry_point.find("=")].strip()
         if utils.on_win:
-            scripts.append("Scripts\\%s-script.py" % cmd)
-            scripts.append("Scripts\\%s.exe" % cmd)
+            scripts.append(f"Scripts\\{cmd}-script.py")
+            scripts.append(f"Scripts\\{cmd}.exe")
         else:
-            scripts.append("bin/%s" % cmd)
+            scripts.append(f"bin/{cmd}")
     return scripts
 
 
@@ -1520,7 +1520,7 @@ def _recurse_symlink_to_size(path, seen=None):
             return _recurse_symlink_to_size(dest, seen=seen)
         elif not isfile(dest):
             # this is a symlink that points to nowhere, so is zero bytes
-            warnings.warn("file %s is a symlink with no target" % path, UserWarning)
+            warnings.warn(f"file {path} is a symlink with no target", UserWarning)
             return 0
 
     return 0
@@ -1764,8 +1764,7 @@ def bundle_conda(output, metadata: MetaData, env, stats, **kw):
                 var = var.split("=", 1)[0]
             elif var not in os.environ:
                 warnings.warn(
-                    "The environment variable '%s' specified in script_env is undefined."
-                    % var,
+                    f"The environment variable '{var}' specified in script_env is undefined.",
                     UserWarning,
                 )
                 val = ""
@@ -3295,9 +3294,9 @@ def test(
                     os.path.dirname(prefix),
                     "_".join(
                         (
-                            "%s_prefix_moved" % name,
+                            f"{name}_prefix_moved",
                             metadata.dist(),
-                            getattr(metadata.config, "%s_subdir" % name),
+                            getattr(metadata.config, f"{name}_subdir"),
                         )
                     ),
                 )
diff --git a/conda_build/cli/main_render.py b/conda_build/cli/main_render.py
index a5cbb8b443..6e6f2bfa41 100644
--- a/conda_build/cli/main_render.py
+++ b/conda_build/cli/main_render.py
@@ -66,7 +66,7 @@ def get_render_parser() -> ArgumentParser:
         "--version",
         action="version",
         help="Show the conda-build version number and exit.",
-        version="conda-build %s" % __version__,
+        version=f"conda-build {__version__}",
     )
     p.add_argument(
         "-n",
diff --git a/conda_build/create_test.py b/conda_build/create_test.py
index 1a8a0f1c34..441fe4a17c 100644
--- a/conda_build/create_test.py
+++ b/conda_build/create_test.py
@@ -122,7 +122,7 @@ def _create_test_files(
                 fo.write(
                     f"{comment_char} tests for {m.dist()} (this is a generated file);\n"
                 )
-                fo.write("print('===== testing package: %s =====');\n" % m.dist())
+                fo.write(f"print('===== testing package: {m.dist()} =====');\n")
 
                 try:
                     with open(test_file) as fi:
@@ -134,7 +134,7 @@ def _create_test_files(
                     fo.write(
                         "# tests were not packaged with this module, and cannot be run\n"
                     )
-                fo.write("\nprint('===== %s OK =====');\n" % m.dist())
+                fo.write(f"\nprint('===== {m.dist()} OK =====');\n")
     return (
         out_file,
         bool(name) and isfile(out_file) and basename(test_file) != "no-file",
@@ -175,8 +175,8 @@ def create_py_files(m: MetaData, test_dir: os.PathLike) -> bool:
     if imports:
         with open(tf, "a") as fo:
             for name in imports:
-                fo.write('print("import: %r")\n' % name)
-                fo.write("import %s\n" % name)
+                fo.write(f'print("import: {name!r}")\n')
+                fo.write(f"import {name}\n")
                 fo.write("\n")
     return tf if (tf_exists or imports) else False
 
@@ -202,8 +202,8 @@ def create_r_files(m: MetaData, test_dir: os.PathLike) -> bool:
     if imports:
         with open(tf, "a") as fo:
             for name in imports:
-                fo.write('print("library(%r)")\n' % name)
-                fo.write("library(%s)\n" % name)
+                fo.write(f'print("library({name!r})")\n')
+                fo.write(f"library({name})\n")
                 fo.write("\n")
     return tf if (tf_exists or imports) else False
 
@@ -225,11 +225,13 @@ def create_pl_files(m: MetaData, test_dir: os.PathLike) -> bool:
                 break
     if tf_exists or imports:
         with open(tf, "a") as fo:
-            print(r'my $expected_version = "%s";' % m.version().rstrip("0"), file=fo)
+            print(
+                r'my $expected_version = "{}";'.format(m.version().rstrip("0")), file=fo
+            )
             if imports:
                 for name in imports:
-                    print(r'print("import: %s\n");' % name, file=fo)
-                    print("use %s;\n" % name, file=fo)
+                    print(rf'print("import: {name}\n");', file=fo)
+                    print(f"use {name};\n", file=fo)
                     # Don't try to print version for complex imports
                     if " " not in name:
                         print(
@@ -264,8 +266,8 @@ def create_lua_files(m: MetaData, test_dir: os.PathLike) -> bool:
     if imports:
         with open(tf, "a+") as fo:
             for name in imports:
-                print(r'print("require \"%s\"\n");' % name, file=fo)
-                print('require "%s"\n' % name, file=fo)
+                print(rf'print("require \"{name}\"\n");', file=fo)
+                print(f'require "{name}"\n', file=fo)
     return tf if (tf_exists or imports) else False
 
 
diff --git a/conda_build/develop.py b/conda_build/develop.py
index 59b31a3231..d0e3d59fd6 100644
--- a/conda_build/develop.py
+++ b/conda_build/develop.py
@@ -137,12 +137,11 @@ def execute(
 ) -> None:
     if not isdir(prefix):
         sys.exit(
-            """\
-Error: environment does not exist: %s
+            f"""\
+Error: environment does not exist: {prefix}
 #
 # Use 'conda create' to create the environment first.
 #"""
-            % prefix
         )
 
     assert find_executable("python", prefix=prefix)
diff --git a/conda_build/environ.py b/conda_build/environ.py
index 5aae94e682..7a3a7ca8cb 100644
--- a/conda_build/environ.py
+++ b/conda_build/environ.py
@@ -536,8 +536,7 @@ def meta_vars(meta: MetaData, skip_build_id=False):
             value = os.getenv(var_name)
         if value is None:
             warnings.warn(
-                "The environment variable '%s' specified in script_env is undefined."
-                % var_name,
+                f"The environment variable '{var_name}' specified in script_env is undefined.",
                 UserWarning,
             )
         else:
@@ -855,7 +854,7 @@ def get_install_actions(
         capture = utils.capture
     for feature, value in feature_list:
         if value:
-            specs.append("%s@" % feature)
+            specs.append(f"{feature}@")
 
     bldpkgs_dirs = ensure_list(bldpkgs_dirs)
 
@@ -961,7 +960,7 @@ def get_install_actions(
                 # specs are the raw specifications, not the conda-derived actual specs
                 #   We're testing that pip etc. are manually specified
                 if not any(
-                    re.match(r"^%s(?:$|[\s=].*)" % pkg, str(dep)) for dep in specs
+                    re.match(rf"^{pkg}(?:$|[\s=].*)", str(dep)) for dep in specs
                 ):
                     precs = [prec for prec in precs if prec.name != pkg]
         cached_precs[(specs, env, subdir, channel_urls, disable_pip)] = precs.copy()
@@ -1341,7 +1340,7 @@ def _display_actions(prefix, precs):
 
     builder = ["", "## Package Plan ##\n"]
     if prefix:
-        builder.append("  environment location: %s" % prefix)
+        builder.append(f"  environment location: {prefix}")
         builder.append("")
     print("\n".join(builder))
 
@@ -1385,9 +1384,9 @@ def channel_filt(s):
             # string with new-style string formatting.
             fmt[pkg] = f"{{pkg:<{maxpkg}}} {{vers:<{maxver}}}"
             if maxchannels:
-                fmt[pkg] += " {channel:<%s}" % maxchannels
+                fmt[pkg] += f" {{channel:<{maxchannels}}}"
             if features[pkg]:
-                fmt[pkg] += " [{features:<%s}]" % maxfeatures
+                fmt[pkg] += f" [{{features:<{maxfeatures}}}]"
 
     lead = " " * 4
 
diff --git a/conda_build/exceptions.py b/conda_build/exceptions.py
index f38706786a..9744ca14b4 100644
--- a/conda_build/exceptions.py
+++ b/conda_build/exceptions.py
@@ -110,19 +110,19 @@ class BuildLockError(CondaBuildException):
 class OverLinkingError(RuntimeError):
     def __init__(self, error, *args):
         self.error = error
-        self.msg = "overlinking check failed \n%s" % (error)
+        self.msg = f"overlinking check failed \n{error}"
         super().__init__(self.msg)
 
 
 class OverDependingError(RuntimeError):
     def __init__(self, error, *args):
         self.error = error
-        self.msg = "overdepending check failed \n%s" % (error)
+        self.msg = f"overdepending check failed \n{error}"
         super().__init__(self.msg)
 
 
 class RunPathError(RuntimeError):
     def __init__(self, error, *args):
         self.error = error
-        self.msg = "runpaths check failed \n%s" % (error)
+        self.msg = f"runpaths check failed \n{error}"
         super().__init__(self.msg)
diff --git a/conda_build/inspect_pkg.py b/conda_build/inspect_pkg.py
index 19c0db7ca3..43fc401551 100644
--- a/conda_build/inspect_pkg.py
+++ b/conda_build/inspect_pkg.py
@@ -132,7 +132,7 @@ def print_linkages(
             else sort_order.get(key[0], (4, key[0]))
         ),
     ):
-        output_string += "%s:\n" % prec
+        output_string += f"{prec}:\n"
         if show_files:
             for lib, path, binary in sorted(links):
                 output_string += f"    {lib} ({path}) from {binary}\n"
@@ -296,7 +296,7 @@ def inspect_linkages(
             output_string += print_linkages(inverted_map[dep], show_files=show_files)
 
     else:
-        raise ValueError("Unrecognized groupby: %s" % groupby)
+        raise ValueError(f"Unrecognized groupby: {groupby}")
     if hasattr(output_string, "decode"):
         output_string = output_string.decode("utf-8")
     return output_string
diff --git a/conda_build/license_family.py b/conda_build/license_family.py
index 976cc1b33a..ab101274ae 100644
--- a/conda_build/license_family.py
+++ b/conda_build/license_family.py
@@ -29,7 +29,7 @@
 gpl3_regex = re.compile("GPL[^2]*3")  # match GPL3
 gpl23_regex = re.compile("GPL[^2]*>= *2")  # match GPL >= 2
 cc_regex = re.compile(r"CC\w+")  # match CC
-punk_regex = re.compile("[%s]" % re.escape(string.punctuation))  # removes punks
+punk_regex = re.compile(f"[{re.escape(string.punctuation)}]")  # removes punks
 
 
 def match_gpl3(family):
diff --git a/conda_build/metadata.py b/conda_build/metadata.py
index 6fd065e0b2..2552682840 100644
--- a/conda_build/metadata.py
+++ b/conda_build/metadata.py
@@ -397,7 +397,7 @@ def ensure_valid_noarch_value(meta):
     build_noarch = meta.get("build", {}).get("noarch")
     if build_noarch and build_noarch not in NOARCH_TYPES:
         raise exceptions.CondaBuildException(
-            "Invalid value for noarch: %s" % build_noarch
+            f"Invalid value for noarch: {build_noarch}"
         )
 
 
@@ -828,7 +828,7 @@ def _get_env_path(env_name_or_path):
                 break
     bootstrap_metadir = os.path.join(env_name_or_path, "conda-meta")
     if not os.path.isdir(bootstrap_metadir):
-        print("Bootstrap environment '%s' not found" % env_name_or_path)
+        print(f"Bootstrap environment '{env_name_or_path}' not found")
         sys.exit(1)
     return env_name_or_path
 
@@ -1478,7 +1478,7 @@ def check_field(key, section):
             if section == "extra":
                 continue
             if section not in FIELDS:
-                raise ValueError("unknown section: %s" % section)
+                raise ValueError(f"unknown section: {section}")
             for key_or_dict in submeta:
                 if section in OPTIONALLY_ITERABLE_FIELDS and isinstance(
                     key_or_dict, dict
@@ -1492,17 +1492,17 @@ def check_field(key, section):
     def name(self) -> str:
         name = self.get_value("package/name", "")
         if not name and self.final:
-            sys.exit("Error: package/name missing in: %r" % self.meta_path)
+            sys.exit(f"Error: package/name missing in: {self.meta_path!r}")
         name = str(name)
         if name != name.lower():
-            sys.exit("Error: package/name must be lowercase, got: %r" % name)
+            sys.exit(f"Error: package/name must be lowercase, got: {name!r}")
         check_bad_chrs(name, "package/name")
         return name
 
     def version(self) -> str:
         version = self.get_value("package/version", "")
         if not version and not self.get_section("outputs") and self.final:
-            sys.exit("Error: package/version missing in: %r" % self.meta_path)
+            sys.exit(f"Error: package/version missing in: {self.meta_path!r}")
         version = str(version)
         check_bad_chrs(version, "package/version")
         if self.final and version.startswith("."):
@@ -1571,7 +1571,7 @@ def ms_depends(self, typ="run"):
             try:
                 ms = MatchSpec(spec)
             except AssertionError:
-                raise RuntimeError("Invalid package specification: %r" % spec)
+                raise RuntimeError(f"Invalid package specification: {spec!r}")
             except (AttributeError, ValueError) as e:
                 raise RuntimeError(
                     "Received dictionary as spec.  Note that pip requirements are "
@@ -1580,7 +1580,7 @@ def ms_depends(self, typ="run"):
             if ms.name == self.name() and not (
                 typ == "build" and self.config.host_subdir != self.config.build_subdir
             ):
-                raise RuntimeError("%s cannot depend on itself" % self.name())
+                raise RuntimeError(f"{self.name()} cannot depend on itself")
             for name, ver in name_ver_list:
                 if ms.name == name:
                     if self.noarch:
@@ -1708,7 +1708,7 @@ def build_id(self):
             out = build_string_from_metadata(self)
             if self.config.filename_hashing and self.final:
                 hash_ = self.hash_dependencies()
-                if not re.findall("h[0-9a-f]{%s}" % self.config.hash_length, out):
+                if not re.findall(f"h[0-9a-f]{{{self.config.hash_length}}}", out):
                     ret = out.rsplit("_", 1)
                     try:
                         int(ret[0])
@@ -1718,14 +1718,14 @@ def build_id(self):
                     if len(ret) > 1:
                         out = "_".join([out] + ret[1:])
                 else:
-                    out = re.sub("h[0-9a-f]{%s}" % self.config.hash_length, hash_, out)
+                    out = re.sub(f"h[0-9a-f]{{{self.config.hash_length}}}", hash_, out)
         return out
 
     def dist(self):
         return f"{self.name()}-{self.version()}-{self.build_id()}"
 
     def pkg_fn(self):
-        return "%s.tar.bz2" % self.dist()
+        return f"{self.dist()}.tar.bz2"
 
     def is_app(self):
         return bool(self.get_value("app/entry"))
@@ -1733,8 +1733,8 @@ def is_app(self):
     def app_meta(self):
         d = {"type": "app"}
         if self.get_value("app/icon"):
-            d["icon"] = "%s.png" % compute_sum(
-                join(self.path, self.get_value("app/icon")), "md5"
+            d["icon"] = "{}.png".format(
+                compute_sum(join(self.path, self.get_value("app/icon")), "md5")
             )
 
         for field, key in [
@@ -2319,7 +2319,7 @@ def variant_in_source(self):
             # constrain the stored variants to only this version in the output
             #     variant mapping
             if re.search(
-                r"\s*\{\{\s*%s\s*(?:.*?)?\}\}" % key, self.extract_source_text()
+                rf"\s*\{{\{{\s*{key}\s*(?:.*?)?\}}\}}", self.extract_source_text()
             ):
                 return True
         return False
diff --git a/conda_build/noarch_python.py b/conda_build/noarch_python.py
index fb81565b3d..1e80fcd2e4 100644
--- a/conda_build/noarch_python.py
+++ b/conda_build/noarch_python.py
@@ -26,7 +26,7 @@ def rewrite_script(fn, prefix):
         try:
             data = fi.read()
         except UnicodeDecodeError:  # file is binary
-            sys.exit("[noarch_python] Noarch package contains binary script: %s" % fn)
+            sys.exit(f"[noarch_python] Noarch package contains binary script: {fn}")
     src_mode = os.stat(src).st_mode
     os.unlink(src)
 
@@ -83,7 +83,7 @@ def handle_file(f, d, prefix):
     else:
         # this should be the built-in logging module, not conda-build's stuff, because this file is standalone.
         log = logging.getLogger(__name__)
-        log.debug("Don't know how to handle file: %s.  Including it as-is." % f)
+        log.debug(f"Don't know how to handle file: {f}.  Including it as-is.")
 
 
 def populate_files(m, files, prefix, entry_point_scripts=None):
@@ -119,7 +119,7 @@ def transform(m, files, prefix):
 
     # Create *nix prelink script
     # Note: it's important to use LF newlines or it wont work if we build on Win
-    with open(join(bin_dir, ".%s-pre-link.sh" % name), "wb") as fo:
+    with open(join(bin_dir, f".{name}-pre-link.sh"), "wb") as fo:
         fo.write(
             b"""\
     #!/bin/bash
@@ -128,7 +128,7 @@ def transform(m, files, prefix):
         )
 
     # Create windows prelink script (be nice and use Windows newlines)
-    with open(join(scripts_dir, ".%s-pre-link.bat" % name), "wb") as fo:
+    with open(join(scripts_dir, f".{name}-pre-link.bat"), "wb") as fo:
         fo.write(
             """\
     @echo off
diff --git a/conda_build/os_utils/ldd.py b/conda_build/os_utils/ldd.py
index b2de763074..84e80b8e90 100644
--- a/conda_build/os_utils/ldd.py
+++ b/conda_build/os_utils/ldd.py
@@ -44,7 +44,7 @@ def ldd(path):
             continue
         if "ld-linux" in line:
             continue
-        raise RuntimeError("Unexpected output from ldd: %s" % line)
+        raise RuntimeError(f"Unexpected output from ldd: {line}")
 
     return res
 
diff --git a/conda_build/os_utils/liefldd.py b/conda_build/os_utils/liefldd.py
index d02cd2bd30..d6ee2841d6 100644
--- a/conda_build/os_utils/liefldd.py
+++ b/conda_build/os_utils/liefldd.py
@@ -1125,9 +1125,9 @@ def get_symbols(file, defined=True, undefined=True, notexported=False, arch="nat
         )
         if binary.__class__ != lief.MachO.Binary:
             if isinstance(s, str):
-                s_name = "%s" % s
+                s_name = f"{s}"
             else:
-                s_name = "%s" % s.name
+                s_name = f"{s.name}"
                 if s.exported and s.imported:
                     print(f"Weird, symbol {s.name} is both imported and exported")
                 if s.exported:
@@ -1136,16 +1136,16 @@ def get_symbols(file, defined=True, undefined=True, notexported=False, arch="nat
                 elif s.imported:
                     is_undefined = False
         else:
-            s_name = "%s" % s.name
+            s_name = f"{s.name}"
             is_notexported = False if s.type & 1 else True
 
         # print("{:32s} : s.type 0b{:020b}, s.value 0b{:020b}".format(s.name, s.type, s.value))
         # print("s.value 0b{:020b} :: s.type 0b{:020b}, {:32s}".format(s.value, s.type, s.name))
         if notexported is True or is_notexported is False:
             if is_undefined and undefined:
-                res.append("%s" % s_name)
+                res.append(f"{s_name}")
             elif not is_undefined and defined:
-                res.append("%s" % s_name)
+                res.append(f"{s_name}")
     return res
 
 
diff --git a/conda_build/os_utils/macho.py b/conda_build/os_utils/macho.py
index 516df7a0a6..17fc5d5a13 100644
--- a/conda_build/os_utils/macho.py
+++ b/conda_build/os_utils/macho.py
@@ -286,7 +286,7 @@ def add_rpath(path, rpath, build_prefix=None, verbose=False):
     args = ["-add_rpath", rpath, path]
     code, _, stderr = install_name_tool(args, build_prefix)
     if "Mach-O dynamic shared library stub file" in stderr:
-        print("Skipping Mach-O dynamic shared library stub file %s\n" % path)
+        print(f"Skipping Mach-O dynamic shared library stub file {path}\n")
         return
     elif "would duplicate path, file already has LC_RPATH for:" in stderr:
         print("Skipping -add_rpath, file already has LC_RPATH set")
@@ -304,7 +304,7 @@ def delete_rpath(path, rpath, build_prefix=None, verbose=False):
     args = ["-delete_rpath", rpath, path]
     code, _, stderr = install_name_tool(args, build_prefix)
     if "Mach-O dynamic shared library stub file" in stderr:
-        print("Skipping Mach-O dynamic shared library stub file %s\n" % path)
+        print(f"Skipping Mach-O dynamic shared library stub file {path}\n")
         return
     elif "no LC_RPATH load command with path:" in stderr:
         print("Skipping -delete_rpath, file doesn't contain that LC_RPATH")
@@ -341,7 +341,7 @@ def install_name_change(path, build_prefix, cb_func, dylibs, verbose=False):
             args.extend(("-change", dylibs[index]["name"], new_name, path))
         code, _, stderr = install_name_tool(args, build_prefix)
         if "Mach-O dynamic shared library stub file" in stderr:
-            print("Skipping Mach-O dynamic shared library stub file %s" % path)
+            print(f"Skipping Mach-O dynamic shared library stub file {path}")
             ret = False
             continue
         else:
diff --git a/conda_build/post.py b/conda_build/post.py
index 30a4057a30..67c6a355a7 100644
--- a/conda_build/post.py
+++ b/conda_build/post.py
@@ -150,11 +150,11 @@ def write_pth(egg_path, config):
     with open(
         join(
             utils.get_site_packages(config.host_prefix, py_ver),
-            "%s.pth" % (fn.split("-")[0]),
+            "{}.pth".format(fn.split("-")[0]),
         ),
         "w",
     ) as fo:
-        fo.write("./%s\n" % fn)
+        fo.write(f"./{fn}\n")
 
 
 def remove_easy_install_pth(files, prefix, config, preserve_egg_dir=False):
@@ -368,7 +368,7 @@ def find_lib(link, prefix, files, path=None):
     if link.startswith(prefix):
         link = normpath(link[len(prefix) + 1 :])
         if not any(link == normpath(w) for w in files):
-            sys.exit("Error: Could not find %s" % link)
+            sys.exit(f"Error: Could not find {link}")
         return link
     if link.startswith("/"):  # but doesn't start with the build prefix
         return
@@ -382,7 +382,7 @@ def find_lib(link, prefix, files, path=None):
         for f in files:
             file_names[basename(f)].append(f)
         if link not in file_names:
-            sys.exit("Error: Could not find %s" % link)
+            sys.exit(f"Error: Could not find {link}")
         if len(file_names[link]) > 1:
             if path and basename(path) == link:
                 # The link is for the file itself, just use it
@@ -403,7 +403,7 @@ def find_lib(link, prefix, files, path=None):
                     "Choosing the first one."
                 )
         return file_names[link][0]
-    print("Don't know how to find %s, skipping" % link)
+    print(f"Don't know how to find {link}, skipping")
 
 
 def osx_ch_link(path, link_dict, host_prefix, build_prefix, files):
@@ -417,8 +417,7 @@ def osx_ch_link(path, link_dict, host_prefix, build_prefix, files):
         )
         if not codefile_class(link, skip_symlinks=True):
             sys.exit(
-                "Error: Compiler runtime library in build prefix not found in host prefix %s"
-                % link
+                f"Error: Compiler runtime library in build prefix not found in host prefix {link}"
             )
         else:
             print(f".. fixing linking of {link} in {path} instead")
@@ -429,7 +428,7 @@ def osx_ch_link(path, link_dict, host_prefix, build_prefix, files):
         return
 
     print(f"Fixing linking of {link} in {path}")
-    print("New link location is %s" % (link_loc))
+    print(f"New link location is {link_loc}")
 
     lib_to_link = relpath(dirname(link_loc), "lib")
     # path_to_lib = utils.relative(path[len(prefix) + 1:])
@@ -647,7 +646,7 @@ def assert_relative_osx(path, host_prefix, build_prefix):
         for prefix in (host_prefix, build_prefix):
             if prefix and name.startswith(prefix):
                 raise RuntimeError(
-                    "library at %s appears to have an absolute path embedded" % path
+                    f"library at {path} appears to have an absolute path embedded"
                 )
 
 
@@ -1770,7 +1769,7 @@ def check_symlinks(files, prefix, croot):
 
     if msgs:
         for msg in msgs:
-            print("Error: %s" % msg, file=sys.stderr)
+            print(f"Error: {msg}", file=sys.stderr)
         sys.exit(1)
 
 
diff --git a/conda_build/render.py b/conda_build/render.py
index b021f8a5b6..cc3bcd87c0 100644
--- a/conda_build/render.py
+++ b/conda_build/render.py
@@ -115,7 +115,7 @@ def _categorize_deps(m, specs, exclude_pattern, variant):
                 # for sake of comparison, ignore dashes and underscores
                 if dash_or_under.sub("", key) == dash_or_under.sub(
                     "", spec_name
-                ) and not re.search(r"%s\s+[0-9a-zA-Z\_\.\<\>\=\*]" % spec_name, spec):
+                ) and not re.search(rf"{spec_name}\s+[0-9a-zA-Z\_\.\<\>\=\*]", spec):
                     dependencies.append(" ".join((spec_name, value)))
         elif exclude_pattern.match(spec):
             pass_through_deps.append(spec)
diff --git a/conda_build/skeletons/cpan.py b/conda_build/skeletons/cpan.py
index c9bd5c398c..31213054d1 100644
--- a/conda_build/skeletons/cpan.py
+++ b/conda_build/skeletons/cpan.py
@@ -511,9 +511,7 @@ def skeletonize(
         # packages, unless we're newer than what's in core
         if metacpan_api_is_core_version(meta_cpan_url, package):
             if not write_core:
-                print(
-                    "We found core module %s. Skipping recipe creation." % packagename
-                )
+                print(f"We found core module {packagename}. Skipping recipe creation.")
                 continue
 
             d["useurl"] = "#"
@@ -577,12 +575,11 @@ def skeletonize(
         version = None
         if exists(dir_path) and not force:
             print(
-                "Directory %s already exists and you have not specified --force "
-                % dir_path
+                f"Directory {dir_path} already exists and you have not specified --force "
             )
             continue
         elif exists(dir_path) and force:
-            print("Directory %s already exists, but forcing recipe creation" % dir_path)
+            print(f"Directory {dir_path} already exists, but forcing recipe creation")
 
         try:
             d["homeurl"] = release_data["resources"]["homepage"]
@@ -756,7 +753,7 @@ def deps_for_package(
     }
     packages_to_append = set()
 
-    print("Processing dependencies for %s..." % package, end="")
+    print(f"Processing dependencies for {package}...", end="")
     sys.stdout.flush()
 
     if not release_data.get("dependency"):
@@ -1052,11 +1049,8 @@ def metacpan_api_is_core_version(cpan_url, module):
             return True
         else:
             sys.exit(
-                (
-                    "Error: Could not find module or distribution named"
-                    " %s on MetaCPAN."
-                )
-                % (module)
+                "Error: Could not find module or distribution named"
+                f" {module} on MetaCPAN."
             )
 
 
diff --git a/conda_build/skeletons/cran.py b/conda_build/skeletons/cran.py
index 38628a52f4..93958333fb 100755
--- a/conda_build/skeletons/cran.py
+++ b/conda_build/skeletons/cran.py
@@ -489,7 +489,7 @@ def dict_from_cran_lines(lines):
                 #   - Suggests in corpcor
                 (k, v) = line.split(":", 1)
         except ValueError:
-            sys.exit("Error: Could not parse metadata (%s)" % line)
+            sys.exit(f"Error: Could not parse metadata ({line})")
         d[k] = v
         # if k not in CRAN_KEYS:
         #     print("Warning: Unknown key %s" % k)
@@ -597,7 +597,7 @@ def read_description_contents(fp):
 
 def get_archive_metadata(path, verbose=True):
     if verbose:
-        print("Reading package metadata from %s" % path)
+        print(f"Reading package metadata from {path}")
     if basename(path) == "DESCRIPTION":
         with open(path, "rb") as fp:
             return read_description_contents(fp)
@@ -614,8 +614,8 @@ def get_archive_metadata(path, verbose=True):
                     fp = zf.open(member, "r")
                     return read_description_contents(fp)
     else:
-        sys.exit("Cannot extract a DESCRIPTION from file %s" % path)
-    sys.exit("%s does not seem to be a CRAN package (no DESCRIPTION) file" % path)
+        sys.exit(f"Cannot extract a DESCRIPTION from file {path}")
+    sys.exit(f"{path} does not seem to be a CRAN package (no DESCRIPTION) file")
 
 
 def get_latest_git_tag(config):
@@ -638,12 +638,12 @@ def get_latest_git_tag(config):
     stdout = stdout.decode("utf-8")
     stderr = stderr.decode("utf-8")
     if stderr or p.returncode:
-        sys.exit("Error: git tag failed (%s)" % stderr)
+        sys.exit(f"Error: git tag failed ({stderr})")
     tags = stdout.strip().splitlines()
     if not tags:
         sys.exit("Error: no tags found")
 
-    print("Using tag %s" % tags[-1])
+    print(f"Using tag {tags[-1]}")
     return tags[-1]
 
 
@@ -683,7 +683,7 @@ def get_cran_archive_versions(cran_url, session, package, verbose=True):
         r.raise_for_status()
     except requests.exceptions.HTTPError as e:
         if e.response.status_code == 404:
-            print("No archive directory for package %s" % package)
+            print(f"No archive directory for package {package}")
             return []
         raise
     versions = []
@@ -698,7 +698,7 @@ def get_cran_archive_versions(cran_url, session, package, verbose=True):
 
 def get_cran_index(cran_url, session, verbose=True):
     if verbose:
-        print("Fetching main index from %s" % cran_url)
+        print(f"Fetching main index from {cran_url}")
     r = session.get(cran_url + "/src/contrib/")
     r.raise_for_status()
     records = {}
@@ -775,7 +775,7 @@ def package_to_inputs_dict(
     """
     if isfile(package):
         return None
-    print("Parsing input package %s:" % package)
+    print(f"Parsing input package {package}:")
     package = strip_end(package, "/")
     package = strip_end(package, sep)
     if "github.com" in package:
@@ -1037,7 +1037,7 @@ def skeletonize(
                 session = get_session(output_dir)
                 cran_index = get_cran_index(cran_url, session)
             if pkg_name.lower() not in cran_index:
-                sys.exit("Package %s not found" % pkg_name)
+                sys.exit(f"Package {pkg_name} not found")
             package, cran_version = cran_index[pkg_name.lower()]
             if cran_version and (not version or version == cran_version):
                 version = cran_version
@@ -1048,8 +1048,7 @@ def skeletonize(
                 sys.exit(1)
             elif not version and not cran_version and not allow_archived:
                 print(
-                    "ERROR: Package %s is archived; to build, use --allow-archived or a --version value"
-                    % pkg_name
+                    f"ERROR: Package {pkg_name} is archived; to build, use --allow-archived or a --version value"
                 )
                 sys.exit(1)
             else:
@@ -1325,7 +1324,7 @@ def skeletonize(
         if cran_package is None:
             cran_package = get_archive_metadata(description_path)
         d["cran_metadata"] = "\n".join(
-            ["# %s" % line for line in cran_package["orig_lines"] if line]
+            [f"# {line}" for line in cran_package["orig_lines"] if line]
         )
 
         # Render the source and binaryN keys
@@ -1377,7 +1376,7 @@ def skeletonize(
             d["summary"] = " " + yaml_quote_string(cran_package["Description"])
 
         if "Suggests" in cran_package and not no_comments:
-            d["suggests"] = "# Suggests: %s" % cran_package["Suggests"]
+            d["suggests"] = "# Suggests: {}".format(cran_package["Suggests"])
         else:
             d["suggests"] = ""
 
@@ -1589,7 +1588,7 @@ def skeletonize(
                                 )
                                 package_list.append(lower_name)
 
-            d["%s_depends" % dep_type] = "".join(deps)
+            d[f"{dep_type}_depends"] = "".join(deps)
 
     if no_comments:
         global CRAN_BUILD_SH_SOURCE, CRAN_META
@@ -1603,7 +1602,7 @@ def skeletonize(
             if update_policy == "error":
                 raise RuntimeError(
                     "directory already exists "
-                    "(and --update-policy is 'error'): %s" % dir_path
+                    f"(and --update-policy is 'error'): {dir_path}"
                 )
             elif update_policy == "overwrite":
                 rm_rf(dir_path)
@@ -1626,7 +1625,7 @@ def skeletonize(
             makedirs(join(dir_path))
         except:
             pass
-        print("Writing recipe for %s" % package.lower())
+        print(f"Writing recipe for {package.lower()}")
         with open(join(dir_path, "meta.yaml"), "w") as f:
             f.write(clear_whitespace(CRAN_META.format(**d)))
         if not exists(join(dir_path, "build.sh")) or update_policy == "overwrite":
@@ -1683,14 +1682,14 @@ def get_outdated(output_dir, cran_index, packages=()):
             continue
 
         if recipe_name not in cran_index:
-            print("Skipping %s, not found on CRAN" % recipe)
+            print(f"Skipping {recipe}, not found on CRAN")
             continue
 
         version_compare(
             join(output_dir, recipe), cran_index[recipe_name][1].replace("-", "_")
         )
 
-        print("Updating %s" % recipe)
+        print(f"Updating {recipe}")
         to_update.append(recipe_name)
 
     return to_update
diff --git a/conda_build/skeletons/luarocks.py b/conda_build/skeletons/luarocks.py
index da8e641928..41ec499bad 100644
--- a/conda_build/skeletons/luarocks.py
+++ b/conda_build/skeletons/luarocks.py
@@ -174,7 +174,7 @@ def package_exists(package_name):
 
 def getval(spec, k):
     if k not in spec:
-        raise Exception("Required key %s not in spec" % k)
+        raise Exception(f"Required key {k} not in spec")
     else:
         return spec[k]
 
@@ -184,7 +184,7 @@ def warn_against_branches(branch):
     print("=========================================")
     print("")
     print("WARNING:")
-    print("Building a rock referenced to branch %s." % branch)
+    print(f"Building a rock referenced to branch {branch}.")
     print("This is not a tag. This is dangerous, because rebuilding")
     print("at a later date may produce a different package.")
     print("Please replace with a tag, git commit, or tarball.")
@@ -253,7 +253,7 @@ def skeletonize(
         package = packages.pop()
 
         packagename = (
-            "lua-%s" % package.lower() if package[:4] != "lua-" else package.lower()
+            f"lua-{package.lower()}" if package[:4] != "lua-" else package.lower()
         )
         d = package_dicts.setdefault(
             package,
@@ -372,13 +372,13 @@ def skeletonize(
                     modules = spec["build"]["platforms"][our_plat]["modules"]
         if modules:
             d["test_commands"] = INDENT.join(
-                [""] + ["""lua -e "require '%s'\"""" % r for r in modules.keys()]
+                [""] + [f"""lua -e "require '{r}'\"""" for r in modules.keys()]
             )
 
     # If we didn't find any modules to import, import the base name
     if d["test_commands"] == "":
         d["test_commands"] = INDENT.join(
-            [""] + ["""lua -e "require '%s'" """ % d["rockname"]]
+            [""] + ["""lua -e "require '{}'" """.format(d["rockname"])]
         )
 
     # Build the luarocks skeleton
diff --git a/conda_build/skeletons/pypi.py b/conda_build/skeletons/pypi.py
index c45c843a6d..d3b716bc8b 100644
--- a/conda_build/skeletons/pypi.py
+++ b/conda_build/skeletons/pypi.py
@@ -300,7 +300,7 @@ def skeletonize(
         if not is_url:
             dir_path = join(output_dir, package.lower())
             if exists(dir_path) and not version_compare:
-                raise RuntimeError("directory already exists: %s" % dir_path)
+                raise RuntimeError(f"directory already exists: {dir_path}")
         d = package_dicts.setdefault(
             package,
             {
@@ -343,14 +343,12 @@ def skeletonize(
             else:
                 # select the most visible version from PyPI.
                 if not versions:
-                    sys.exit(
-                        "Error: Could not find any versions of package %s" % package
-                    )
+                    sys.exit(f"Error: Could not find any versions of package {package}")
                 if len(versions) > 1:
-                    print("Warning, the following versions were found for %s" % package)
+                    print(f"Warning, the following versions were found for {package}")
                     for ver in versions:
                         print(ver)
-                    print("Using %s" % versions[-1])
+                    print(f"Using {versions[-1]}")
                     print("Use --version to specify a different version.")
                 d["version"] = versions[-1]
 
@@ -404,7 +402,7 @@ def skeletonize(
         d = package_dicts[package]
         name = d["packagename"].lower()
         makedirs(join(output_dir, name))
-        print("Writing recipe for %s" % package.lower())
+        print(f"Writing recipe for {package.lower()}")
         with open(join(output_dir, name, "meta.yaml"), "w") as f:
             rendered_recipe = PYPI_META_HEADER.format(**d)
 
@@ -642,8 +640,8 @@ def get_download_data(
             if not urls[0]["url"]:
                 # The package doesn't have a url, or maybe it only has a wheel.
                 sys.exit(
-                    "Error: Could not build recipe for %s. "
-                    "Could not find any valid urls." % package
+                    f"Error: Could not build recipe for {package}. "
+                    "Could not find any valid urls."
                 )
             U = parse_url(urls[0]["url"])
             if not U.path:
@@ -652,9 +650,9 @@ def get_download_data(
             fragment = U.fragment or ""
             digest = fragment.split("=")
         else:
-            sys.exit("Error: No source urls found for %s" % package)
+            sys.exit(f"Error: No source urls found for {package}")
     if len(urls) > 1 and not noprompt:
-        print("More than one source version is available for %s:" % package)
+        print(f"More than one source version is available for {package}:")
         if manual_url:
             for i, url in enumerate(urls):
                 print(
@@ -689,7 +687,7 @@ def get_download_data(
         filename = url["filename"] or "package"
     else:
         # User provided a URL, try to use it.
-        print("Using url %s" % package)
+        print(f"Using url {package}")
         pypiurl = package
         U = parse_url(package)
         digest = U.fragment.split("=")
@@ -711,7 +709,7 @@ def version_compare(package, versions):
 
     recipe_dir = abspath(package.lower())
     if not isdir(recipe_dir):
-        sys.exit("Error: no such directory: %s" % recipe_dir)
+        sys.exit(f"Error: no such directory: {recipe_dir}")
     m = MetaData(recipe_dir)
     local_version = nv(m.version())
     print(f"Local recipe for {package} has version {local_version}")
@@ -721,11 +719,11 @@ def version_compare(package, versions):
         # Comparing normalized versions, displaying non normalized ones
         new_versions = versions[: norm_versions.index(local_version)]
         if len(new_versions) > 0:
-            print("Following new versions of %s are avaliable" % (package))
+            print(f"Following new versions of {package} are avaliable")
             for ver in new_versions:
                 print(ver)
         else:
-            print("No new version for %s is available" % (package))
+            print(f"No new version for {package} is available")
         sys.exit()
 
 
@@ -828,7 +826,7 @@ def get_package_metadata(
     config,
     setup_options,
 ):
-    print("Downloading %s" % package)
+    print(f"Downloading {package}")
     print("PyPI URL: ", metadata["pypiurl"])
     pkginfo = get_pkginfo(
         package,
@@ -982,7 +980,7 @@ def _spec_from_line(line):
                     )
                     spec = _spec_from_line(dep_orig)
                 if spec is None:
-                    sys.exit("Error: Could not parse: %s" % dep)
+                    sys.exit(f"Error: Could not parse: {dep}")
 
             if marker:
                 spec = " ".join((spec, marker))
@@ -1058,10 +1056,10 @@ def get_license_name(package, pkginfo, no_prompt=False, data=None):
         if no_prompt:
             return license_name
         elif "\n" not in license_name:
-            print('Using "%s" for the license' % license_name)
+            print(f'Using "{license_name}" for the license')
         else:
             # Some projects put the whole license text in this field
-            print("This is the license for %s" % package)
+            print(f"This is the license for {package}")
             print()
             print(license_name)
             print()
@@ -1070,8 +1068,8 @@ def get_license_name(package, pkginfo, no_prompt=False, data=None):
         license_name = "UNKNOWN"
     else:
         license_name = input(
-            "No license could be found for %s on PyPI or in the source. "
-            "What license should I use? " % package
+            f"No license could be found for {package} on PyPI or in the source. "
+            "What license should I use? "
         )
     return license_name
 
@@ -1175,7 +1173,7 @@ def unpack(src_path, tempdir):
     if src_path.lower().endswith(decompressible_exts):
         tar_xf(src_path, tempdir)
     else:
-        raise Exception("not a valid source: %s" % src_path)
+        raise Exception(f"not a valid source: {src_path}")
 
 
 def get_dir(tempdir):
@@ -1209,7 +1207,7 @@ def get_requirements(package, pkginfo, all_extras=True):
         try:
             extras_require = [pkginfo["extras_require"][x] for x in extras]
         except KeyError:
-            sys.exit("Error: Invalid extra features: [%s]" % ",".join(extras))
+            sys.exit("Error: Invalid extra features: [{}]".format(",".join(extras)))
         # match PEP 508 environment markers; currently only matches the
         #  subset of environment markers that compare to python_version
         #  using a single basic Python comparison operator
@@ -1297,10 +1295,10 @@ def get_pkginfo(
         else:
             new_hash_value = ""
 
-        print("Unpacking %s..." % package)
+        print(f"Unpacking {package}...")
         unpack(join(config.src_cache, filename), tempdir)
         print("done")
-        print("working in %s" % tempdir)
+        print(f"working in {tempdir}")
         src_dir = get_dir(tempdir)
         # TODO: find args parameters needed by run_setuppy
         run_setuppy(
@@ -1366,7 +1364,7 @@ def run_setuppy(src_dir, temp_dir, python_version, extra_specs, config, setup_op
     )
     stdlib_dir = join(
         config.host_prefix,
-        "Lib" if on_win else "lib/python%s" % python_version,
+        "Lib" if on_win else f"lib/python{python_version}",
     )
 
     patch = join(temp_dir, "pypi-distutils.patch")
@@ -1421,8 +1419,8 @@ def run_setuppy(src_dir, temp_dir, python_version, extra_specs, config, setup_op
     try:
         check_call_env(cmdargs, env=env)
     except subprocess.CalledProcessError:
-        print("$PYTHONPATH = %s" % env["PYTHONPATH"])
-        sys.exit("Error: command failed: %s" % " ".join(cmdargs))
+        print("$PYTHONPATH = {}".format(env["PYTHONPATH"]))
+        sys.exit("Error: command failed: {}".format(" ".join(cmdargs)))
     finally:
         chdir(cwd)
 
diff --git a/conda_build/source.py b/conda_build/source.py
index c7b3d1921b..903f5d7ca0 100644
--- a/conda_build/source.py
+++ b/conda_build/source.py
@@ -55,7 +55,7 @@ def append_hash_to_fn(fn, hash_value):
 def download_to_cache(cache_folder, recipe_path, source_dict, verbose=False):
     """Download a source to the local cache."""
     if verbose:
-        log.info("Source cache directory is: %s" % cache_folder)
+        log.info(f"Source cache directory is: {cache_folder}")
     if not isdir(cache_folder) and not os.path.islink(cache_folder):
         os.makedirs(cache_folder)
 
@@ -81,10 +81,10 @@ def download_to_cache(cache_folder, recipe_path, source_dict, verbose=False):
     path = join(cache_folder, fn)
     if isfile(path):
         if verbose:
-            log.info("Found source in cache: %s" % fn)
+            log.info(f"Found source in cache: {fn}")
     else:
         if verbose:
-            log.info("Downloading source to cache: %s" % fn)
+            log.info(f"Downloading source to cache: {fn}")
 
         for url in source_urls:
             if "://" not in url:
@@ -98,14 +98,14 @@ def download_to_cache(cache_folder, recipe_path, source_dict, verbose=False):
                     url = "file:///" + expanduser(url[8:]).replace("\\", "/")
             try:
                 if verbose:
-                    log.info("Downloading %s" % url)
+                    log.info(f"Downloading {url}")
                 with LoggingContext():
                     download(url, path)
             except CondaHTTPError as e:
-                log.warn("Error: %s" % str(e).strip())
+                log.warn(f"Error: {str(e).strip()}")
                 rm_rf(path)
             except RuntimeError as e:
-                log.warn("Error: %s" % str(e).strip())
+                log.warn(f"Error: {str(e).strip()}")
                 rm_rf(path)
             else:
                 if verbose:
@@ -113,7 +113,7 @@ def download_to_cache(cache_folder, recipe_path, source_dict, verbose=False):
                 break
         else:  # no break
             rm_rf(path)
-            raise RuntimeError("Could not download %s" % url)
+            raise RuntimeError(f"Could not download {url}")
 
     hashed = None
     for tp in ("md5", "sha1", "sha256"):
@@ -344,7 +344,7 @@ def git_mirror_checkout_recursive(
             )
             checkout = output.decode("utf-8")
         if verbose:
-            print("checkout: %r" % checkout)
+            print(f"checkout: {checkout!r}")
         if checkout:
             check_call_env(
                 [git, "checkout", checkout],
@@ -492,7 +492,7 @@ def git_info(src_dir, build_prefix, git=None, verbose=True, fo=None):
             stdout = check_output_env(cmd, stderr=stderr, cwd=src_dir, env=env)
         except CalledProcessError as e:
             if check_error:
-                raise Exception("git error: %s" % str(e))
+                raise Exception(f"git error: {str(e)}")
         encoding = locale.getpreferredencoding()
         if not fo:
             encoding = sys.stdout.encoding
@@ -535,7 +535,7 @@ def hg_source(source_dict, src_dir, hg_cache, verbose):
     # now clone in to work directory
     update = source_dict.get("hg_tag") or "tip"
     if verbose:
-        print("checkout: %r" % update)
+        print(f"checkout: {update!r}")
 
     check_call_env(["hg", "clone", cache_repo, src_dir], stdout=stdout, stderr=stderr)
     check_call_env(
@@ -953,7 +953,7 @@ def try_apply_patch(patch, patch_args, cwd, stdout, stderr):
 
     exception = None
     if not isfile(path):
-        raise RuntimeError("Error: no such patch: %s" % path)
+        raise RuntimeError(f"Error: no such patch: {path}")
 
     if config.verbose:
         stdout = None
diff --git a/conda_build/tarcheck.py b/conda_build/tarcheck.py
index 3a98559187..374422f1e1 100644
--- a/conda_build/tarcheck.py
+++ b/conda_build/tarcheck.py
@@ -13,7 +13,7 @@ def dist_fn(fn):
     elif fn.endswith(".tar.bz2"):
         return fn[:-8]
     else:
-        raise Exception("did not expect filename: %r" % fn)
+        raise Exception(f"did not expect filename: {fn!r}")
 
 
 class TarCheck:
@@ -51,9 +51,9 @@ def info_files(self):
             return
         for p in sorted(seta | setb):
             if p not in seta:
-                print("%r not in info/files" % p)
+                print(f"{p!r} not in info/files")
             if p not in setb:
-                print("%r not in tarball" % p)
+                print(f"{p!r} not in tarball")
         raise Exception("info/files")
 
     def index_json(self):
diff --git a/conda_build/utils.py b/conda_build/utils.py
index 4a3e1f782c..796f849caf 100644
--- a/conda_build/utils.py
+++ b/conda_build/utils.py
@@ -425,7 +425,7 @@ def bytes2human(n):
         if n >= prefix[s]:
             value = float(n) / prefix[s]
             return f"{value:.1f}{s}"
-    return "%sB" % n
+    return f"{n}B"
 
 
 def seconds2human(s):
@@ -458,7 +458,7 @@ def get_recipe_abspath(recipe):
                 tar_xf(recipe_tarfile, os.path.join(recipe_dir, "info"))
             need_cleanup = True
         else:
-            print("Ignoring non-recipe: %s" % recipe)
+            print(f"Ignoring non-recipe: {recipe}")
             return (None, None)
     else:
         recipe_dir = abspath(os.path.join(os.getcwd(), recipe))
@@ -1054,7 +1054,7 @@ def iter_entry_points(items):
     for item in items:
         m = entry_pat.match(item)
         if m is None:
-            sys.exit("Error cound not match entry point: %r" % item)
+            sys.exit(f"Error cound not match entry point: {item!r}")
         yield m.groups()
 
 
@@ -1076,7 +1076,7 @@ def create_entry_point(path, module, func, config):
             os.remove(path)
         with open(path, "w") as fo:
             if not config.noarch:
-                fo.write("#!%s\n" % config.host_python)
+                fo.write(f"#!{config.host_python}\n")
             fo.write(pyscript)
         os.chmod(path, 0o775)
 
@@ -1951,7 +1951,7 @@ def insert_variant_versions(requirements_dict, variant, env):
     )
     reqs = ensure_list(requirements_dict.get(env))
     for key, val in variant.items():
-        regex = re.compile(r"^(%s)(?:\s*$)" % key.replace("_", "[-_]"))
+        regex = re.compile(r"^({})(?:\s*$)".format(key.replace("_", "[-_]")))
         matches = [regex.match(pkg) for pkg in reqs]
         if any(matches):
             for i, x in enumerate(matches):
diff --git a/conda_build/variants.py b/conda_build/variants.py
index 1e2b1adc0c..447025818c 100644
--- a/conda_build/variants.py
+++ b/conda_build/variants.py
@@ -745,13 +745,13 @@ def find_used_variables_in_text(variant, recipe_text, selectors_only=False):
             continue
         v_regex = re.escape(v)
         v_req_regex = "[-_]".join(map(re.escape, v.split("_")))
-        variant_regex = r"\{\s*(?:pin_[a-z]+\(\s*?['\"])?%s[^'\"]*?\}\}" % v_regex
-        selector_regex = r"^[^#\[]*?\#?\s\[[^\]]*?(?<![_\w\d])%s[=\s<>!\]]" % v_regex
+        variant_regex = rf"\{{\s*(?:pin_[a-z]+\(\s*?['\"])?{v_regex}[^'\"]*?\}}\}}"
+        selector_regex = rf"^[^#\[]*?\#?\s\[[^\]]*?(?<![_\w\d]){v_regex}[=\s<>!\]]"
         conditional_regex = (
             r"(?:^|[^\{])\{%\s*(?:el)?if\s*.*" + v_regex + r"\s*(?:[^%]*?)?%\}"
         )
         # plain req name, no version spec.  Look for end of line after name, or comment or selector
-        requirement_regex = r"^\s+\-\s+%s\s*(?:\s[\[#]|$)" % v_req_regex
+        requirement_regex = rf"^\s+\-\s+{v_req_regex}\s*(?:\s[\[#]|$)"
         if selectors_only:
             all_res.insert(0, selector_regex)
         else:
diff --git a/conda_build/windows.py b/conda_build/windows.py
index 706b499265..00287c50bf 100644
--- a/conda_build/windows.py
+++ b/conda_build/windows.py
@@ -56,16 +56,13 @@ def fix_staged_scripts(scripts_dir, config):
             # If it's a #!python script
             if not (line.startswith(b"#!") and b"python" in line.lower()):
                 continue
-            print(
-                "Adjusting unix-style #! script %s, "
-                "and adding a .bat file for it" % fn
-            )
+            print(f"Adjusting unix-style #! script {fn}, and adding a .bat file for it")
             # copy it with a .py extension (skipping that first #! line)
             with open(join(scripts_dir, fn + "-script.py"), "wb") as fo:
                 fo.write(f.read())
             # now create the .exe file
             copy_into(
-                join(dirname(__file__), "cli-%s.exe" % config.host_arch),
+                join(dirname(__file__), f"cli-{config.host_arch}.exe"),
                 join(scripts_dir, fn + ".exe"),
             )
 
@@ -338,7 +335,7 @@ def build(m, bld_bat, stats, provision_only=False):
             rewrite_env = {
                 k: env[k] for k in ["PREFIX", "BUILD_PREFIX", "SRC_DIR"] if k in env
             }
-            print("Rewriting env in output: %s" % pprint.pformat(rewrite_env))
+            print(f"Rewriting env in output: {pprint.pformat(rewrite_env)}")
         check_call_env(
             cmd, cwd=m.config.work_dir, stats=stats, rewrite_stdout_env=rewrite_env
         )
diff --git a/docs/scrape_help.py b/docs/scrape_help.py
index 2f99fbb403..66d5af1e57 100755
--- a/docs/scrape_help.py
+++ b/docs/scrape_help.py
@@ -112,7 +112,7 @@ def external_commands():
 
     def get_help(command):
         command_help[command] = conda_command_help(command)
-        print("Checked for subcommand help for %s" % command)
+        print(f"Checked for subcommand help for {command}")
 
     with ThreadPoolExecutor(len(commands)) as executor:
         # list() is needed for force exceptions to be raised
@@ -164,7 +164,7 @@ def generate_man(command):
             [
                 "help2man",
                 "--name",
-                "conda %s" % command,
+                f"conda {command}",
                 "--section",
                 "1",
                 "--source",
@@ -172,36 +172,34 @@ def generate_man(command):
                 "--version-string",
                 conda_version,
                 "--no-info",
-                "conda %s" % command,
+                f"conda {command}",
             ]
         )
         retries -= 1
 
     if not manpage:
-        sys.exit("Error: Could not get help for conda %s" % command)
+        sys.exit(f"Error: Could not get help for conda {command}")
 
     replacements = man_replacements()
     for text in replacements:
         manpage = manpage.replace(text, replacements[text])
-    with open(join(manpath, "conda-%s.1" % command.replace(" ", "-")), "w") as f:
+    with open(join(manpath, "conda-{}.1".format(command.replace(" ", "-"))), "w") as f:
         f.write(manpage)
 
-    print("Generated manpage for conda %s" % command)
+    print(f"Generated manpage for conda {command}")
 
 
 def generate_html(command):
     command_file = command.replace(" ", "-")
 
     # Use abspath so that it always has a path separator
-    man = Popen(
-        ["man", abspath(join(manpath, "conda-%s.1" % command_file))], stdout=PIPE
-    )
+    man = Popen(["man", abspath(join(manpath, f"conda-{command_file}.1"))], stdout=PIPE)
     htmlpage = check_output(
         [
             "man2html",
             "-bare",  # Don't use HTML, HEAD, or BODY tags
             "title",
-            "conda-%s" % command_file,
+            f"conda-{command_file}",
             "-topm",
             "0",  # No top margin
             "-botm",
@@ -210,14 +208,14 @@ def generate_html(command):
         stdin=man.stdout,
     )
 
-    with open(join(manpath, "conda-%s.html" % command_file), "wb") as f:
+    with open(join(manpath, f"conda-{command_file}.html"), "wb") as f:
         f.write(htmlpage)
-    print("Generated html for conda %s" % command)
+    print(f"Generated html for conda {command}")
 
 
 def write_rst(command, sep=None):
     command_file = command.replace(" ", "-")
-    with open(join(manpath, "conda-%s.html" % command_file)) as f:
+    with open(join(manpath, f"conda-{command_file}.html")) as f:
         html = f.read()
 
     rp = rstpath
@@ -225,13 +223,13 @@ def write_rst(command, sep=None):
         rp = join(rp, sep)
     if not isdir(rp):
         makedirs(rp)
-    with open(join(rp, "conda-%s.rst" % command_file), "w") as f:
+    with open(join(rp, f"conda-{command_file}.rst"), "w") as f:
         f.write(RST_HEADER.format(command=command))
         for line in html.splitlines():
             f.write("   ")
             f.write(line)
             f.write("\n")
-    print("Generated rst for conda %s" % command)
+    print(f"Generated rst for conda {command}")
 
 
 def main():
diff --git a/tests/test_api_build_conda_v2.py b/tests/test_api_build_conda_v2.py
index 4c0c09b9ac..dc4078e61f 100644
--- a/tests/test_api_build_conda_v2.py
+++ b/tests/test_api_build_conda_v2.py
@@ -40,4 +40,4 @@ def test_conda_pkg_format(
 
     # Verify that test pass ran through api
     assert "Manual entry point" in out
-    assert "TEST END: %s" % output_file in out
+    assert f"TEST END: {output_file}" in out
diff --git a/tests/utils.py b/tests/utils.py
index b4ed64912b..4d6803f09d 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -91,8 +91,7 @@ def assert_package_consistency(package_path):
                 has_prefix_present = False
     except tarfile.ReadError:
         raise RuntimeError(
-            "Could not extract metadata from %s. "
-            "File probably corrupt." % package_path
+            f"Could not extract metadata from {package_path}. File probably corrupt."
         )
     errors = []
     member_set = set(member_list)  # The tar format allows duplicates in member_list
@@ -101,7 +100,7 @@ def assert_package_consistency(package_path):
     file_set = set(file_list)
     # Check that there are no duplicates in info/files
     if len(file_list) != len(file_set):
-        errors.append("Duplicate files in info/files in %s" % package_path)
+        errors.append(f"Duplicate files in info/files in {package_path}")
     # Compare the contents of files and members
     unlisted_members = member_set.difference(file_set)
     missing_members = file_set.difference(member_set)
@@ -109,14 +108,16 @@ def assert_package_consistency(package_path):
     missing_files = [m for m in unlisted_members if not m.startswith("info/")]
     if len(missing_files) > 0:
         errors.append(
-            "The following package files are not listed in "
-            "info/files: %s" % ", ".join(missing_files)
+            "The following package files are not listed in info/files: {}".format(
+                ", ".join(missing_files)
+            )
         )
     # Find any files missing in the archive
     if len(missing_members) > 0:
         errors.append(
-            "The following files listed in info/files are missing: "
-            "%s" % ", ".join(missing_members)
+            "The following files listed in info/files are missing: {}".format(
+                ", ".join(missing_members)
+            )
         )
     # Find any files in has_prefix that are not present in files
     if has_prefix_present:
@@ -129,15 +130,15 @@ def assert_package_consistency(package_path):
             elif len(parts) == 3:
                 prefix_path_list.append(parts[2])
             else:
-                errors.append("Invalid has_prefix file in package: %s" % package_path)
+                errors.append(f"Invalid has_prefix file in package: {package_path}")
         prefix_path_set = set(prefix_path_list)
         if len(prefix_path_list) != len(prefix_path_set):
-            errors.append("Duplicate files in info/has_prefix in %s" % package_path)
+            errors.append(f"Duplicate files in info/has_prefix in {package_path}")
         prefix_not_in_files = prefix_path_set.difference(file_set)
         if len(prefix_not_in_files) > 0:
             errors.append(
                 "The following files listed in info/has_prefix are missing "
-                "from info/files: %s" % ", ".join(prefix_not_in_files)
+                "from info/files: {}".format(", ".join(prefix_not_in_files))
             )
 
     # Assert that no errors are detected