diff --git a/lib/battery.js b/lib/battery.js
index 3d05e38..48a7248 100644
--- a/lib/battery.js
+++ b/lib/battery.js
@@ -57,7 +57,7 @@ module.exports = function (callback) {
           battery_path = '/sys/class/power_supply/BAT0/';
         }
         if (battery_path) {
-          exec('cat ' + battery_path + 'uevent', function (error, stdout) {
+          fs.readFile(battery_path + 'uevent', function (error, stdout) {
             if (!error) {
               let lines = stdout.toString().split('\n');
 
@@ -67,7 +67,7 @@ module.exports = function (callback) {
               result.capacityUnit = result.voltage ? 'mWh' : 'mAh';
               result.cyclecount = parseInt('0' + util.getValue(lines, 'POWER_SUPPLY_CYCLE_COUNT', '='), 10);
               result.maxcapacity = Math.round(parseInt('0' + util.getValue(lines, 'POWER_SUPPLY_CHARGE_FULL', '='), 10) / 1000.0 / (result.voltage || 1));
-              result.designedcapacity = Math.round(parseInt('0' + util.getValue(lines, 'POWER_SUPPLY_CHARGE_FULL_DESIGN', '='), 10) / 1000.0 / (result.voltage || 1))| result.maxcapacity;
+              result.designedcapacity = Math.round(parseInt('0' + util.getValue(lines, 'POWER_SUPPLY_CHARGE_FULL_DESIGN', '='), 10) / 1000.0 / (result.voltage || 1)) | result.maxcapacity;
               result.currentcapacity = Math.round(parseInt('0' + util.getValue(lines, 'POWER_SUPPLY_CHARGE_NOW', '='), 10) / 1000.0 / (result.voltage || 1));
               if (!result.maxcapacity) {
                 result.maxcapacity = parseInt('0' + util.getValue(lines, 'POWER_SUPPLY_ENERGY_FULL', '='), 10) / 1000.0;
@@ -100,6 +100,9 @@ module.exports = function (callback) {
               result.serial = util.getValue(lines, 'POWER_SUPPLY_SERIAL_NUMBER', '=');
               if (callback) { callback(result); }
               resolve(result);
+            } else {
+              if (callback) { callback(result); }
+              resolve(result);
             }
           });
         } else {
diff --git a/lib/cpu.js b/lib/cpu.js
index 388e988..ed8901d 100644
--- a/lib/cpu.js
+++ b/lib/cpu.js
@@ -780,7 +780,7 @@ function cpuTemperature(callback) {
           } else {
             fs.stat('/sys/class/thermal/thermal_zone0/temp', function (err) {
               if (err === null) {
-                exec('cat /sys/class/thermal/thermal_zone0/temp', function (error, stdout) {
+                fs.readFile('/sys/class/thermal/thermal_zone0/temp', function (error, stdout) {
                   if (!error) {
                     let lines = stdout.toString().split('\n');
                     if (lines.length > 0) {
@@ -928,7 +928,7 @@ function cpuFlags(callback) {
             });
           }
           if (!result) {
-            exec('cat /proc/cpuinfo', function (error, stdout) {
+            fs.readFile('/proc/cpuinfo', function (error, stdout) {
               if (!error) {
                 let lines = stdout.toString().split('\n');
                 result = util.getValue(lines, 'features', ':', true).toLowerCase();
diff --git a/lib/filesystem.js b/lib/filesystem.js
index 19ff183..6790a39 100755
--- a/lib/filesystem.js
+++ b/lib/filesystem.js
@@ -16,6 +16,7 @@
 const exec = require('child_process').exec;
 const execSync = require('child_process').execSync;
 const util = require('./util');
+const fs = require('fs');
 
 let _platform = process.platform;
 
@@ -159,8 +160,7 @@ function fsOpenFiles(callback) {
         });
       }
       if (_linux) {
-        let cmd = 'cat /proc/sys/fs/file-nr';
-        exec(cmd, function (error, stdout) {
+        fs.readFile('/proc/sys/fs/file-nr', function (error, stdout) {
           if (!error) {
             let lines = stdout.toString().split('\n');
             if (lines[0]) {
diff --git a/lib/memory.js b/lib/memory.js
index 88e2f03..e6b23c6 100644
--- a/lib/memory.js
+++ b/lib/memory.js
@@ -17,6 +17,7 @@ const os = require('os');
 const exec = require('child_process').exec;
 const execSync = require('child_process').execSync;
 const util = require('./util');
+const fs = require('fs');
 
 let _platform = process.platform;
 
@@ -143,7 +144,7 @@ function mem(callback) {
       };
 
       if (_linux) {
-        exec('export LC_ALL=C; cat /proc/meminfo 2>/dev/null ; unset LC_ALL', function (error, stdout) {
+        fs.readFile('/proc/meminfo', function (error, stdout) {
           if (!error) {
             const lines = stdout.toString().split('\n');
             result.total = parseInt(util.getValue(lines, 'memtotal'), 10);
diff --git a/lib/system.js b/lib/system.js
index 9650f72..7a730f9 100644
--- a/lib/system.js
+++ b/lib/system.js
@@ -88,7 +88,7 @@ function system(callback) {
 
               if (result.manufacturer === '' && result.model === 'Computer' && result.version === '') {
                 // Check Raspberry Pi
-                exec('cat /proc/cpuinfo', function (error, stdout) {
+                fs.readFile('/proc/cpuinfo', function (error, stdout) {
                   if (!error) {
                     let lines = stdout.toString().split('\n');
                     result.model = util.getValue(lines, 'hardware', ':', true).toUpperCase();