Reboot does not run at all

I followed this piece of command copied from this site

http://ift.tt/1E909qZ

importing the certificates on your Android device

Copy the files to the /sdcard folder, either with any file manager or with adb push.

Go into adb shell (adb shell from commandline), or open the 'terminal'-application on your android device. You will get a command prompt similar like shell@android:/ $
Gain superuser/root rights, neccessary to perform privileged actions:
  su
Make the /system folder writable (will return to read-only upon reboot):
  mount -o remount,rw /system
Copy the new certificate files to the correct folder on your Android device:
  cp /sdcard/5ed36f99.0 /system/etc/security/cacerts/
  cp /sdcard/e5662767.0 /system/etc/security/cacerts/
Correct the file permissions to u=rw, g=r, o=r:
  cd /system/etc/security/cacerts/
  chmod 644 5ed36f99.0
  chmod 644 e5662767.0
Check if the files are ok:
  ls -al -Z
Omit '-Z' if you are using a version of Android without SElinux, it just shows some extra security settings which might be useful if you run into trouble. Amongst the other default android certificate files, you will see the two new files: -rw-r–r– root root u:object_r:system_file:s0 5ed36f99.0 and -rw-r–r– root root u:object_r:system_file:s0 e5662767.0
The certificates will be loaded upon the next boot of your device, so reboot your device:

  reboot

The moment i hit the command reboot. My android emulator from my android studio emulator hangs. Nothing seems to happen with reboot and the files that i placed in the system folder is also missing.

Does reboot take a very long time as i only waited about 2mins.

Basically what happened is that after i ran remount. I ran adb devices and it shows me that emulator - 5554 is offline. why is this so when my emulator is running perfectly well