diff --git a/src/Access/examples/kerberos_init.cpp b/src/Access/examples/kerberos_init.cpp
index 5dbe92a5b57..f9f9d882ece 100644
--- a/src/Access/examples/kerberos_init.cpp
+++ b/src/Access/examples/kerberos_init.cpp
@@ -25,7 +25,7 @@ int main(int argc, char ** argv)
         return 0;
     }
 
-    String cache_name = "";
+    const char * cache_name = "";
     if (argc == 4)
         cache_name = argv[3];
 
diff --git a/src/Common/CompactArray.h b/src/Common/CompactArray.h
index cf97206edb8..c2dd696d651 100644
--- a/src/Common/CompactArray.h
+++ b/src/Common/CompactArray.h
@@ -130,7 +130,7 @@ public:
 private:
     ReadBuffer & in;
     /// The physical location of the current cell.
-    Locus locus;
+    Locus locus{};
     /// The current position in the file as a cell number.
     BucketIndex current_bucket_index = 0;
     /// The number of bytes read.
diff --git a/src/Core/examples/coro.cpp b/src/Core/examples/coro.cpp
index 956b4e988e4..370820a228d 100644
--- a/src/Core/examples/coro.cpp
+++ b/src/Core/examples/coro.cpp
@@ -12,7 +12,7 @@
 #if defined(__clang__)
 #include <experimental/coroutine>
 
-namespace std
+namespace std // NOLINT(cert-dcl58-cpp)
 {
     using namespace experimental::coroutines_v1;
 }
@@ -97,14 +97,14 @@ struct Task
     static bool resumeImpl(Task *r)
     {
         if (r->value)
-        return false;
+            return false;
 
         auto & next = r->my.promise().next;
 
         if (next)
         {
             if (resumeImpl(next.promise().r))
-            return true;
+                return true;
             next = {};
         }
 
@@ -183,7 +183,7 @@ int main()
         auto t = foo("foo");
         std::cout << ".. started" << std::endl;
         while (t.resume())
-        std::cout << ".. yielded" << std::endl;
+            std::cout << ".. yielded" << std::endl;
         std::cout << ".. done: " << t.res() << std::endl;
     }
     catch (DB::Exception & e)
diff --git a/src/Interpreters/examples/hash_map3.cpp b/src/Interpreters/examples/hash_map3.cpp
index a8673e06e9b..110dcab3f76 100644
--- a/src/Interpreters/examples/hash_map3.cpp
+++ b/src/Interpreters/examples/hash_map3.cpp
@@ -1,13 +1,9 @@
-#include <iostream>
-
 #define DBMS_HASH_MAP_DEBUG_RESIZES
 #define DBMS_HASH_MAP_COUNT_COLLISIONS
 
-
-#include <string.h>
-
+#include <iostream>
+#include <cstring>
 #include <cstdlib>
-
 #include <utility>
 
 #include <base/types.h>
diff --git a/src/Storages/examples/get_current_inserts_in_replicated.cpp b/src/Storages/examples/get_current_inserts_in_replicated.cpp
index d7dedbcab9c..0d04cbd260e 100644
--- a/src/Storages/examples/get_current_inserts_in_replicated.cpp
+++ b/src/Storages/examples/get_current_inserts_in_replicated.cpp
@@ -85,7 +85,7 @@ try
         for (BlockInfo & block : block_infos)
         {
             Coordination::GetResponse resp = block.contents_future.get();
-            if (resp.error == Coordination::Error::ZOK && lock_holder_paths.count(resp.data))
+            if (resp.error == Coordination::Error::ZOK && lock_holder_paths.contains(resp.data))
             {
                 ++total_count;
                 current_inserts[block.partition].insert(block.number);
diff --git a/utils/compressor/decompress_perf.cpp b/utils/compressor/decompress_perf.cpp
index 20f974aab7f..e3210164d79 100644
--- a/utils/compressor/decompress_perf.cpp
+++ b/utils/compressor/decompress_perf.cpp
@@ -1,5 +1,5 @@
 #include <lz4.h>
-#include <string.h>
+#include <cstring>
 #include <optional>
 #include <base/types.h>
 
@@ -60,7 +60,7 @@ protected:
         compressed_in->readStrict(reinterpret_cast<char *>(&checksum), sizeof(checksum));
 
         own_compressed_buffer.resize(COMPRESSED_BLOCK_HEADER_SIZE);
-        compressed_in->readStrict(&own_compressed_buffer[0], COMPRESSED_BLOCK_HEADER_SIZE);
+        compressed_in->readStrict(own_compressed_buffer.data(), COMPRESSED_BLOCK_HEADER_SIZE);
 
         UInt8 method = own_compressed_buffer[0];    /// See CompressedWriteBuffer.h
 
@@ -90,7 +90,7 @@ protected:
         else
         {
             own_compressed_buffer.resize(size_compressed + (variant == LZ4_REFERENCE ? 0 : LZ4::ADDITIONAL_BYTES_AT_END_OF_BUFFER));
-            compressed_buffer = &own_compressed_buffer[0];
+            compressed_buffer = own_compressed_buffer.data();
             compressed_in->readStrict(compressed_buffer + COMPRESSED_BLOCK_HEADER_SIZE, size_compressed - COMPRESSED_BLOCK_HEADER_SIZE);
         }
 
@@ -143,7 +143,7 @@ private:
             return false;
 
         memory.resize(size_decompressed + LZ4::ADDITIONAL_BYTES_AT_END_OF_BUFFER);
-        working_buffer = Buffer(&memory[0], &memory[size_decompressed]);
+        working_buffer = Buffer(memory.data(), &memory[size_decompressed]);
 
         decompress(working_buffer.begin(), size_decompressed, size_compressed_without_checksum);
 
diff --git a/utils/db-generator/query_db_generator.cpp b/utils/db-generator/query_db_generator.cpp
index 18c9bdbca38..00785af89f7 100644
--- a/utils/db-generator/query_db_generator.cpp
+++ b/utils/db-generator/query_db_generator.cpp
@@ -1,6 +1,6 @@
 #include <map>
 #include <cstdlib>
-#include <stdio.h>
+#include <cstdio>
 #include <iostream>
 #include <string>
 
@@ -59,8 +59,8 @@ std::string randomDate()
     int32_t month = rng() % 12 + 1;
     int32_t day = rng() % 12 + 1;
     char answer[13];
-    sprintf(answer, "'%04u-%02u-%02u'", year, month, day);
-    return std::string(answer);
+    size_t size = sprintf(answer, "'%04u-%02u-%02u'", year, month, day);
+    return std::string(answer, size);
 }
 
 std::string randomDatetime()
@@ -72,7 +72,7 @@ std::string randomDatetime()
     int32_t minutes = rng() % 60;
     int32_t seconds = rng() % 60;
     char answer[22];
-    sprintf(
+    size_t size = sprintf(
             answer,
             "'%04u-%02u-%02u %02u:%02u:%02u'",
             year,
@@ -81,7 +81,7 @@ std::string randomDatetime()
             hours,
             minutes,
             seconds);
-    return std::string(answer);
+    return std::string(answer, size);
 }
 TableAndColumn get_table_a_column(const std::string & c)
 {
diff --git a/utils/graphite-rollup/graphite-rollup-bench.cpp b/utils/graphite-rollup/graphite-rollup-bench.cpp
index 49a3d509be6..a46d214edbf 100644
--- a/utils/graphite-rollup/graphite-rollup-bench.cpp
+++ b/utils/graphite-rollup/graphite-rollup-bench.cpp
@@ -4,7 +4,6 @@
 #include <iomanip>
 #include <iostream>
 #include <stdexcept>
-#include <system_error>
 
 #include <boost/program_options.hpp>
 
@@ -15,50 +14,35 @@
 #include <Common/Config/ConfigProcessor.h>
 #include <Common/Exception.h>
 #include <Interpreters/Context.h>
+#include <IO/ReadBufferFromFile.h>
+#include <IO/ReadHelpers.h>
 
 using namespace DB;
 
 static SharedContextHolder shared_context = Context::createShared();
 
-std::vector<std::string_view> loadMetrics(const std::string & metrics_file)
+auto loadMetrics(const std::string & metrics_file)
 {
-    std::vector<std::string_view> metrics;
+    std::vector<std::string> metrics;
+    ReadBufferFromFile in(metrics_file);
+    String line;
 
-    FILE * stream;
-    char * line = nullptr;
-    size_t len = 0;
-    ssize_t nread;
-
-    stream = fopen(metrics_file.c_str(), "r");
-    if (stream == nullptr)
+    while (!in.eof())
     {
-        throw std::runtime_error(strerror(errno));
-    }
-
-    while ((nread = getline(&line, &len, stream)) != -1) /// NOLINT
-    {
-        size_t l = strlen(line);
-        if (l > 0)
+        readEscapedStringUntilEOL(line, in);
+        if (!in.eof())
         {
-            if (line[l - 1] == '\n')
-            {
-                line[l - 1] = '\0';
-                l--;
-            }
-            if (l > 0)
-            {
-                metrics.emplace_back(std::string_view(strdup(line), l));
-            }
+            ++in.position();
+        }
+        if (!line.empty() && line.back() == '\n')
+        {
+            line.pop_back();
+        }
+        if (!line.empty())
+        {
+            metrics.emplace_back(line);
         }
     }
-    free(line);
-    if (ferror(stream))
-    {
-        fclose(stream);
-        throw std::runtime_error(strerror(errno));
-    }
-
-    fclose(stream);
 
     return metrics;
 }
@@ -80,7 +64,7 @@ void bench(const std::string & config_path, const std::string & metrics_file, si
     Graphite::Params params;
     setGraphitePatternsFromConfig(context, "graphite_rollup", params);
 
-    std::vector<std::string_view> metrics = loadMetrics(metrics_file);
+    auto metrics = loadMetrics(metrics_file);
 
     std::vector<double> durations(metrics.size());
     size_t j, i;
@@ -99,15 +83,14 @@ void bench(const std::string & config_path, const std::string & metrics_file, si
 
             if (j == 0 && verbose)
             {
-                std::cout << metrics[i].data() << ": rule with regexp '" << rule.second->regexp_str << "' found\n";
+                std::cout << metrics[i] << ": rule with regexp '" << rule.second->regexp_str << "' found\n";
             }
         }
     }
 
     for (i = 0; i < metrics.size(); i++)
     {
-        std::cout << metrics[i].data() << " " << durations[i] / n << " ns\n";
-        free(const_cast<void *>(static_cast<const void *>(metrics[i].data())));
+        std::cout << metrics[i] << " " << durations[i] / n << " ns\n";
     }
 }
 
diff --git a/utils/iotest/iotest.cpp b/utils/iotest/iotest.cpp
index f23ee6929fa..7a1f35ddd52 100644
--- a/utils/iotest/iotest.cpp
+++ b/utils/iotest/iotest.cpp
@@ -15,8 +15,7 @@
 #include <vector>
 
 #include <fcntl.h>
-#include <stdlib.h>
-#include <time.h>
+#include <ctime>
 #include <unistd.h>
 
 
@@ -54,7 +53,7 @@ void thread(int fd, int mode, size_t min_offset, size_t max_offset, size_t block
     if ((mode & MODE_DIRECT))
         buf = direct_buf.data();
     else
-        buf = &simple_buf[0];
+        buf = simple_buf.data();
 
     pcg64 rng(randomSeed());
 
diff --git a/utils/iotest/iotest_aio.cpp b/utils/iotest/iotest_aio.cpp
index 05074bc85f4..c0cf002ce58 100644
--- a/utils/iotest/iotest_aio.cpp
+++ b/utils/iotest/iotest_aio.cpp
@@ -110,12 +110,12 @@ void thread(int fd, int mode, size_t min_offset, size_t max_offset, size_t block
         }
 
         /// Send queries.
-        if  (io_submit(ctx.ctx, query_cbs.size(), &query_cbs[0]) < 0)
+        if  (io_submit(ctx.ctx, query_cbs.size(), query_cbs.data()) < 0)
             throwFromErrno("io_submit failed", ErrorCodes::CANNOT_IO_SUBMIT);
 
         /// Receive answers. If we have something else to send, then receive at least one answer (after that send them), otherwise wait all answers.
-        memset(&events[0], 0, buffers_count * sizeof(events[0]));
-        int evs = io_getevents(ctx.ctx, (blocks_sent < count ? 1 : in_progress), buffers_count, &events[0], nullptr);
+        memset(events.data(), 0, buffers_count * sizeof(events[0]));
+        int evs = io_getevents(ctx.ctx, (blocks_sent < count ? 1 : in_progress), buffers_count, events.data(), nullptr);
         if (evs < 0)
             throwFromErrno("io_getevents failed", ErrorCodes::CANNOT_IO_GETEVENTS);
 
diff --git a/utils/iotest/iotest_nonblock.cpp b/utils/iotest/iotest_nonblock.cpp
index 430e951d36b..33fab4d04e6 100644
--- a/utils/iotest/iotest_nonblock.cpp
+++ b/utils/iotest/iotest_nonblock.cpp
@@ -13,8 +13,8 @@
 
 #include <fcntl.h>
 #include <poll.h>
-#include <stdlib.h>
-#include <time.h>
+#include <cstdlib>
+#include <ctime>
 #include <unistd.h>
 
 #if defined (OS_LINUX)
@@ -101,7 +101,7 @@ int mainImpl(int argc, char ** argv)
     size_t ops = 0;
     while (ops < count)
     {
-        if (poll(&polls[0], descriptors, -1) <= 0)
+        if (poll(polls.data(), descriptors, -1) <= 0)
             throwFromErrno("poll failed", ErrorCodes::SYSTEM_ERROR);
         for (size_t i = 0; i < descriptors; ++i)
         {
@@ -123,12 +123,12 @@ int mainImpl(int argc, char ** argv)
 
             if (mode == MODE_READ)
             {
-                if (static_cast<int>(block_size) != pread(fds[i], &buf[0], block_size, offset))
+                if (static_cast<int>(block_size) != pread(fds[i], buf.data(), block_size, offset))
                     throwFromErrno("Cannot read", ErrorCodes::CANNOT_READ_FROM_FILE_DESCRIPTOR);
             }
             else
             {
-                if (static_cast<int>(block_size) != pwrite(fds[i], &buf[0], block_size, offset))
+                if (static_cast<int>(block_size) != pwrite(fds[i], buf.data(), block_size, offset))
                     throwFromErrno("Cannot write", ErrorCodes::CANNOT_WRITE_TO_FILE_DESCRIPTOR);
             }
         }
diff --git a/utils/zookeeper-adjust-block-numbers-to-parts/main.cpp b/utils/zookeeper-adjust-block-numbers-to-parts/main.cpp
index 5c694ee04ef..7736921a9c6 100644
--- a/utils/zookeeper-adjust-block-numbers-to-parts/main.cpp
+++ b/utils/zookeeper-adjust-block-numbers-to-parts/main.cpp
@@ -179,8 +179,8 @@ void setCurrentBlockNumber(zkutil::ZooKeeper & zk, const std::string & path, Int
             if (number != current_block_number)
             {
                 char suffix[11] = "";
-                sprintf(suffix, "%010lld", current_block_number);
-                std::string expected_path = block_prefix + suffix;
+                size_t size = sprintf(suffix, "%010lld", current_block_number);
+                std::string expected_path = block_prefix + std::string(suffix, size);
                 std::cerr << "\t" << path_created << ": Ephemeral node has been created with an unexpected path (expected something like "
                           << expected_path << ")." << std::endl;
                 return false;
diff --git a/utils/zookeeper-test/main.cpp b/utils/zookeeper-test/main.cpp
index 5d0b54aa74b..2d5f2ba34ab 100644
--- a/utils/zookeeper-test/main.cpp
+++ b/utils/zookeeper-test/main.cpp
@@ -238,9 +238,9 @@ std::string currentDateTime()
     tstruct = *localtime(&now);
     // Visit http://en.cppreference.com/w/cpp/chrono/c/strftime
     // for more information about date/time format
-    strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S", &tstruct);
+    size_t size = strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S", &tstruct);
 
-    return buf;
+    return std::string(buf, size);
 }