diff --git a/include/modules/custom.hpp b/include/modules/custom.hpp
index 6d987b26..79bd7604 100644
--- a/include/modules/custom.hpp
+++ b/include/modules/custom.hpp
@@ -2,8 +2,8 @@
 
 #include <fmt/format.h>
 #include <iostream>
-#include <sys/wait.h>
 #include "util/chrono.hpp"
+#include "util/command.hpp"
 #include "ALabel.hpp"
 
 namespace waybar::modules {
diff --git a/include/util/chrono.hpp b/include/util/chrono.hpp
index f0ad9a7b..09ac5b27 100644
--- a/include/util/chrono.hpp
+++ b/include/util/chrono.hpp
@@ -8,85 +8,85 @@
 
 namespace waybar::chrono {
 
-    using namespace std::chrono;
+using namespace std::chrono;
 
-    using clock = std::chrono::system_clock;
-    using duration = clock::duration;
-    using time_point = std::chrono::time_point<clock, duration>;
+using clock = std::chrono::system_clock;
+using duration = clock::duration;
+using time_point = std::chrono::time_point<clock, duration>;
 
-    inline struct timespec to_timespec(time_point t) noexcept
-    {
-      long secs = duration_cast<seconds>(t.time_since_epoch()).count();
-      long nsc = duration_cast<nanoseconds>(t.time_since_epoch() % seconds(1)).count();
-      return {secs, nsc};
-    }
+inline struct timespec to_timespec(time_point t) noexcept
+{
+  long secs = duration_cast<seconds>(t.time_since_epoch()).count();
+  long nsc = duration_cast<nanoseconds>(t.time_since_epoch() % seconds(1)).count();
+  return {secs, nsc};
+}
 
-    inline time_point to_time_point(struct timespec t) noexcept
-    {
-      return time_point(duration_cast<duration>(seconds(t.tv_sec) + nanoseconds(t.tv_nsec)));
-    }
+inline time_point to_time_point(struct timespec t) noexcept
+{
+  return time_point(duration_cast<duration>(seconds(t.tv_sec) + nanoseconds(t.tv_nsec)));
+}
 
 }
 
 namespace waybar::util {
 
-  struct SleeperThread {
-    SleeperThread() = default;
+struct SleeperThread {
+  SleeperThread() = default;
 
-    SleeperThread(std::function<void()> func)
-      : thread{[this, func] {
-          do {
-            func();
-          } while (do_run);
-        }}
-    {
-      defined = true;
-    }
-
-    SleeperThread& operator=(std::function<void()> func)
-    {
-      thread = std::thread([this, func] {
+  SleeperThread(std::function<void()> func)
+    : thread{[this, func] {
         do {
           func();
         } while (do_run);
-      });
-      defined = true;
-      return *this;
-    }
+      }}
+  {
+    defined = true;
+  }
+
+  SleeperThread& operator=(std::function<void()> func)
+  {
+    thread = std::thread([this, func] {
+      do {
+        func();
+      } while (do_run);
+    });
+    defined = true;
+    return *this;
+  }
 
 
-    auto sleep_for(chrono::duration dur)
-    {
-      auto lock = std::unique_lock(mutex);
-      return condvar.wait_for(lock, dur);
-    }
+  auto sleep_for(chrono::duration dur)
+  {
+    auto lock = std::unique_lock(mutex);
+    return condvar.wait_for(lock, dur);
+  }
 
-    auto sleep_until(chrono::time_point time)
-    {
-      auto lock = std::unique_lock(mutex);
-      return condvar.wait_until(lock, time);
-    }
+  auto sleep_until(chrono::time_point time)
+  {
+    auto lock = std::unique_lock(mutex);
+    return condvar.wait_until(lock, time);
+  }
 
-    auto wake_up()
-    {
+  auto wake_up()
+  {
+    condvar.notify_all();
+  }
+
+  ~SleeperThread()
+  {
+    do_run = false;
+    if (defined) {
       condvar.notify_all();
+      thread.join();
     }
+  }
 
-    ~SleeperThread()
-    {
-      do_run = false;
-      if (defined) {
-        condvar.notify_all();
-        thread.join();
-      }
-    }
-
-  private:
-    std::thread thread;
-    std::condition_variable condvar;
-    std::mutex mutex;
-    bool defined = false;
-    bool do_run = true;
-  };
+private:
+  std::thread thread;
+  std::condition_variable condvar;
+  std::mutex mutex;
+  bool defined = false;
+  bool do_run = true;
+};
 
 }
diff --git a/include/util/command.hpp b/include/util/command.hpp
new file mode 100644
index 00000000..80773cb5
--- /dev/null
+++ b/include/util/command.hpp
@@ -0,0 +1,35 @@
+#pragma once
+
+#include <sys/wait.h>
+
+namespace waybar::util::command {
+
+struct cmd_res {
+  int exit_code;
+  std::string out;
+};
+
+inline struct cmd_res exec(const std::string cmd)
+{
+  FILE* fp(popen(cmd.c_str(), "r"));
+  if (!fp) {
+    return { -1, "" };
+  }
+
+  std::array<char, 128> buffer = {0};
+  std::string output;
+  while (feof(fp) == 0) {
+    if (fgets(buffer.data(), 128, fp) != nullptr) {
+      output += buffer.data();
+    }
+  }
+
+  // Remove last newline
+  if (!output.empty() && output[output.length()-1] == '\n') {
+    output.erase(output.length()-1);
+  }
+  int exit_code = WEXITSTATUS(pclose(fp));
+  return { exit_code, output };
+}
+
+}
diff --git a/include/util/json.hpp b/include/util/json.hpp
index 53b93458..6c2db959 100644
--- a/include/util/json.hpp
+++ b/include/util/json.hpp
@@ -4,31 +4,31 @@
 
 namespace waybar::util {
 
-  struct JsonParser {
+struct JsonParser {
 
-    JsonParser()
-      : _reader(_builder.newCharReader())
-    {}
+  JsonParser()
+    : _reader(_builder.newCharReader())
+  {}
 
-    Json::Value parse(const std::string data)
-    {
-      Json::Value root;
-      std::string err;
-      bool res =
-        _reader->parse(data.c_str(), data.c_str() + data.size(), &root, &err);
-      if (!res)
-        throw std::runtime_error(err);
-      return root;
-    }
+  Json::Value parse(const std::string data)
+  {
+    Json::Value root;
+    std::string err;
+    bool res =
+      _reader->parse(data.c_str(), data.c_str() + data.size(), &root, &err);
+    if (!res)
+      throw std::runtime_error(err);
+    return root;
+  }
 
-    ~JsonParser()
-    {
-      delete _reader;
-    }
+  ~JsonParser()
+  {
+    delete _reader;
+  }
 
-  private:
-    Json::CharReaderBuilder _builder;
-    Json::CharReader *_reader;
-  };
+private:
+  Json::CharReaderBuilder _builder;
+  Json::CharReader *_reader;
+};
 
 }
diff --git a/src/modules/custom.cpp b/src/modules/custom.cpp
index e192f808..d298c54d 100644
--- a/src/modules/custom.cpp
+++ b/src/modules/custom.cpp
@@ -10,22 +10,8 @@ waybar::modules::Custom::Custom(std::string name, Json::Value config)
   thread_ = [this, interval] {
     bool can_update = true;
     if (config_["exec-if"]) {
-      auto pid = fork();
-      int res = 0;
-      if (pid == 0) {
-        std::istringstream iss(config_["exec-if"].asString());
-        std::vector<char*> av;
-        for (std::string s; iss >> s;) {
-          // Need to copy otherwise values are the same
-          char *str = new char[s.size() + 1];
-          memcpy(str, s.c_str(), s.size() + 1);
-          av.push_back(str);
-        }
-        av.push_back(0);
-        execvp(av.front(), av.data());
-        _exit(127);
-      } else if (pid > 0 && waitpid(pid, &res, 0) != -1
-        && WEXITSTATUS(res) != 0) {
+      auto res = waybar::util::command::exec(config_["exec-if"].asString());
+      if (res.exit_code != 0) {
         can_update = false;
       }
     }
@@ -38,33 +24,16 @@ waybar::modules::Custom::Custom(std::string name, Json::Value config)
 
 auto waybar::modules::Custom::update() -> void
 {
-  std::array<char, 128> buffer = {0};
-  std::string output;
-  std::shared_ptr<FILE> fp(popen(config_["exec"].asCString(), "r"), pclose);
-  if (!fp) {
-    std::cerr << name_ + " can't exec " + config_["exec"].asString() << std::endl;
-    return;
-  }
-
-  while (feof(fp.get()) == 0) {
-    if (fgets(buffer.data(), 128, fp.get()) != nullptr) {
-        output += buffer.data();
-    }
-  }
-
-  // Remove last newline
-  if (!output.empty() && output[output.length()-1] == '\n') {
-    output.erase(output.length()-1);
-  }
+  auto res = waybar::util::command::exec(config_["exec"].asString());
 
   // Hide label if output is empty
-  if (output.empty()) {
+  if (res.out.empty() || res.exit_code != 0) {
     label_.hide();
     label_.set_name("");
   } else {
     label_.set_name("custom-" + name_);
     auto format = config_["format"] ? config_["format"].asString() : "{}";
-    auto str = fmt::format(format, output);
+    auto str = fmt::format(format, res.out);
     label_.set_text(str);
     label_.set_tooltip_text(str);
     label_.show();