system: show the kernel version

src/system.js

@@ -4,6 +4,7 @@ exports = module.exports = {
     reboot,
     getInfo,
     getUbuntuVersion,
+    getKernelVersion,
     getSwaps,
     checkDiskSpace,
     getMemory,
@@ -358,6 +359,13 @@ async function checkRebootRequired() {
     }
 }
 
+async function getKernelVersion() {
+    const data = safe.fs.readFileSync('/proc/version', 'utf-8');
+    if (data === null) throw new BoxError(BoxError.FS_ERROR, safe.error.message);
+    const version = data.match(/^Linux version (\S+)/)[1];
+    return `Linux ${version}`;
+}
+
 async function getUbuntuVersion() {
     const release = safe.fs.readFileSync('/etc/lsb-release', 'utf-8');
     if (release === null) throw new BoxError(BoxError.FS_ERROR, safe.error.message);