Ubuntu Repair Command

The mod_rewrite module allows us to rewrite URLs in a cleaner fashion, translating human-readable paths into code-friendly query strings or redirecting URLs based on additional conditions. With it, users can easily modify file systems, delete them, create new ones, and even fix issues they might have. User Configuration. The Following command can be used to check and repair all MySQL databases on a Ubuntu or Debian Linux System. bicycle repair. Deploy your production Ubuntu OpenStack cloud across a rack of physical servers. 04 LTS as the main Ubuntu OS for most of us users by the end of the year. I am still fairly new to Debian, so I do not know if both statements will work, but I did use "apt-get --reinstall install xserver-xfree86" to reinstall a damaged xserver. First, I will show you how to boot into Ubuntu 18. Install Boot-Repair application than can be used to repair Grub on Ubuntu Linux. Dispone di: Pulsante per riparare i più frequenti problemi d'avvio (riparare filesystem, reinstallare Grub2). This guide is for users who are running Ubuntu versions 16. Related Posts. Functionalities same functionalities as the normal Ubuntu 12. So, finally, I upgraded Windows 8. The Heroku Command Line Interface (CLI) makes it easy to create and manage your Heroku apps directly from the terminal. File system. This should now be visible when executing the command ip link once more. If your company uses the Ubuntu Linux operating system rather than Windows, the chkdsk command. 9 on Ubuntu and Linuxmint operating system. The exit code returned by fsck is the sum of the following conditions: 0 - No errors 1 - File system errors corrected. To find out your exact command reboot, select Ubuntu and press Esc when you see the countdown. How to Recover a Damaged Memory Card in Ubuntu. Personal Package Archives are repositories that are hosted on the Launchpad, and are used to upgrade or install packages that aren’t usually available in the official repositories of Ubuntu. @fmonegaglia It depends. This short article will list the most common. I try to install Ubuntu Linux on a Acer Predator G3-605 (dual boot with the preinstalled Windows 8. [email protected]:~# sudo mount /dev/sdaX /mnt replace X with your drive number on which Ubuntu | Kali (Linux OS) Installed Installing grub needs access of some directories, so we need to bind them one by one using command line for detecting previously installed operating system. How To Install All Kali Linux Tools On Ubuntu? Using few simple commands, we can easily install Kali Linux tools on our Ubuntu machine. We have run the commands and procedures mentioned in this article on a Ubuntu 18. Adding Linux to the Vista Bootloader. Once you have the command prompt up on screen, you will need to issue a set of commands to find and resolve issues that might be preventing. List all hard disks connected to a Ubuntu system Submitted by admin, on February 1st, 2013 You often need to know what physical drives are attached to a system, how many drives are connected, or even what device names match up with which physical drive. USE BOOT-REPAIR: Launch Boot-Repair, then click the "Recommended repair. 04 Linux is to right. So for those who need to install grub using the ubuntu dapper (and above) livecd, here they are: Open the terminal and enter the following commands. You can find out more from the Ubuntu MATE Raspberry Pi page and the Ubuntu MATE UMPC page. cfg file with the menu entries. 04 using the apt package manager. To run administrative tasks in Linux, you must have root (also known as superuser) access. 04 Bionic Beaver Linux Bring up network management window by right-click on the top right corner network icon and locate the network connection you. 04 LTS CD, but also :. Fix "Ubuntu WiFi is disabled by hardware switch" on Ubuntu 16. First, go back into your setup and put it back in UEFI mode if you installed Ubuntu that way. list, or in /etc/apt/sources. Note: Ubuntu 18. Type your sudo password. 04 LTS will have 5 years support with updates and upgrades whenever necessary being released. Here's the output of both commands. Today I am going to tell you how to use a simple, small software to solve most. That should activate your first ethernet adapter and run dhclient to get it an address via DHCP. When I restarted it, Windows failed to load and the automatic repair loop kicked in. Using another computer, browse to the Ubuntu website and download the copy that is right for your architecture. Repair Ubuntu running in a Virtual Machine Bruce Fulton Demonstrated with a VM running Ubuntu Server 10. Fix it with Startup Repair and BootRec Commands. Personal Package Archives are repositories that are hosted on the Launchpad, and are used to upgrade or install packages that aren't usually available in the official repositories of Ubuntu. For this run the df -Th command. If in doubt, grab the 32-bit version, as this will boot on any machine. 5 (Ubuntu 1:1. Personal Package Archives are repositories that are hosted on the Launchpad, and are used to upgrade or install packages that aren’t usually available in the official repositories of Ubuntu. Source Packages. Update the system executing the command: sudo apt-get update. What you’ll need to have is the latest version of bootable Ubuntu mounted on your USB drive. For example, you are learning Linux bash shell scripting from the Internet. Repair Windows BCD Repair Windows boot Dual boot Windows 7 and Linux/UNIX Repair Windows 7 boot How to install Windows 8 to VHD How to move Windows 7 boot files to another drive/partition ARC Paths - dual-boot on Windows XP Fix: The drive where Windows is installed is locked. Ubuntu now available from the Windows Store! at the command-line. Then you've come to the right place because this tutorial will show you step by step how to repair grub in Linux Mint and Ubuntu. For Ubuntu Server, use the command below to edit the Grub configuration file: sudo nano /etc/default/grub. Above commands give you detail information about Ubuntu version. I’ve moved the Ubuntu Dock and window controls, set a different GTK and icon theme, changed the wallpaper, and adjusted a few other settings:. Step-by-step process to Remove Ubuntu From Dual Boot Windows 10:-. Linux is free, open source and a great operating system, but it will not suit each one of us. As you may already know, the recently released Windows 10 build 14316 comes with the Ubuntu Bash console kit and utils. 1 to Windows 10 last night. All you need to do is to select a problem from the list and click OK to get it resolved. Booting into Ubuntu live USB. Before jumping into the command line, you have to make sure about the specific broken package. Before we get started, make sure your server has all the latest software updates installed. Adding Linux to the Vista Bootloader. It's more of a stunt than practical, but this unlikely marriage of Ubuntu and Windows is interesting to play with. The world of Ubuntu welcomes you and it is ready to grant you all the power over your system. Next, we install Boot Repair by executing the following command: sudo apt-get install -y boot-repair Step 2: Run Boot Repair on Ubuntu. In this guide, you will discover a number of different ways to open an application using Ubuntu. How to Cut, Copy, and Paste in the Terminal in Ubuntu 218. Download YeoWorks and Run the. dkpg is still a pre-requisite for passing LPIC-1 certification. list, or in /etc/apt/sources. sudo dpkg –configure -a. Then you need to restore your original MBR and it can be done easily with Boot Repair using Ubuntu Live CD / USB. This mode just loads some basic services and drops you into command line mode. In a few simple steps, we will explain, how to automate your system tasks on Ubuntu, using the crontab in Ubuntu. There may be times where you need or want to boot up a Linux system without using a GUI, that is with no X, but rather opt for the command line. Ubuntu Trusty 32bit Ubuntu Trusty 64bit Ubuntu Xenial through Artful 64bit Ubuntu Bionic through Disco 64bit Previous Versions. We will be using a well known tool "Boot Repair" to accomplish this task. Repair Windows BCD Repair Windows boot Dual boot Windows 7 and Linux/UNIX Repair Windows 7 boot How to install Windows 8 to VHD How to move Windows 7 boot files to another drive/partition ARC Paths - dual-boot on Windows XP Fix: The drive where Windows is installed is locked. I am still fairly new to Debian, so I do not know if both statements will work, but I did use "apt-get --reinstall install xserver-xfree86" to reinstall a damaged xserver. Do you know how to reinstall it to work again? Output from sudo dpkg --configure -a : dp. ext3 -f /dev/sda5 to perform a disk check (assuming that Ubuntu is installed alongside Windows on your hard disk in the standard configuration). If you're asked for a password, type in facepunch and hit. The project is open source. @fmonegaglia It depends. We all encounter many times the boot related problems and most of them are simply related to GRUB. Fsck command needs to be run with superuser How to Install Ubuntu Alongside With Windows 10 or 8. 04, I have listed out a few recommended steps that you can follow to get started with it. The exit code returned by fsck is the sum of the following conditions: 0 - No errors 1 - File system errors corrected. Another easy way how to open Terminal on Ubuntu Bionic Beaver 18. Then type the following commands in the terminal mkdir 3. If you are using Ubuntu Linux, its a good idea to keep recovery tool installed in the system. 04 and Linux Mint 14 / 13; How To Install Nvidia 325. You can then remove the CD or USB device and continue to do your work from system memory. How to repair Ubuntu if it won't boot. To upgrade to Ubuntu 18. If you're recently installed Ubuntu alongside Windows 8 (dual-boot) and now get the errors: "can't find command 'drivemap'" and "invalid EFI file path" when you try to start Windows, this tutorial will explain how to fix it. Once rebooted, open a PowerShell/command prompt and run “Bash” and follow the simple prompts to accept Canonical’s license and kick-off the download of the Ubuntu image: After download has completed, you’ll be able to start “Bash on Ubuntu on Windows” from the Start menu: Enjoy! Related Release Notes. In this article, we. The open source community offers a variety of tools that offer real value to any IT Support personal working with Data Recovery. If you are interested in the information of a particular node id, then you can do so by passing the command: lightning-cli listnodes. Boot-Repair will be launched automatically. Update instructions. 04, I have listed out a few recommended steps that you can follow to get started with it. A drop-down menu is shown. 04 (Precise Pangolin) Linux Mint 13 ; Method 1 If you are able to reach the login screen, press CTRL+ALT+F2 to enter CLI mode, then enter your login credentials and kill Xserver with this command: sudo service lightdm stop Uninstall now the current AMD driver with these commands:. Use the commands on the screen to install all the updates. Get the name of the network interface with the ip link command. Until the system boots completely, there’s no network stack, so you won’t be able to access the system through ssh. How to Execute a. I'm a bit new to ubuntu. I wanted to test it with fsck and tell it to repair any file system errors. You can use it to boot multiple operating systems easily, including triple-boot setups with Boot Camp. 2? I'm running Ubuntu 12. It's still a beta release, so there are some rough edges, but it provides easy access to various tools using its wizard, Rescapp. There are two ways to make use of Gparted. or-Boot from Install disc > Click Next > click Repair your computer > click Troubleshoot > click Advanced options > choose Command Prompt. Many of these commands are compatible with other GNU/Linux distributions. In this tutorial, we will show you how to install Python Pip on Ubuntu 18. Using another computer, browse to the Ubuntu website and download the copy that is right for your architecture. For Apache, this looks like service httpd restart will issue a restart command to Apache. In Ubuntu, the safe mode is called the recovery mode, and if the system fails to boot for any reason, It may be useful to boot it into Recovery Mode. dd (command line utility) Startup Disk Creator. XFS is not the default file system for Debian or Ubuntu Linux based system. Example 1:. If you've decided that Ubuntu is no longer the right operating system for you, then you might be wondering how to go about deleting it from your system. ) create a boot info summary (to provide input for when asking for help in forums. What is your business doing to prepare for 2030? Hear from Michael Dell and top executives as they define a new decade and redefine IT. But don’t worry, We will give you 10 basic Linux commands & important commands that will help you get started. Repair Filesystem Errors in Ubuntu with fsck I have an ATA 80GB HDD in my laptop now, which is, well yes, old and has some issues. Depending on when was the last time a file system was checked, the system runs the fsck during boot time to check whether the filesystem is in consistent state. In this case, deleting single file will be a tedious job. In this guide we'll show you how to speed up Ubuntu 18. Rescatux is a repair distribution designed to fix problems with both Linux and Windows. Access the terminal window by clicking Applications then Accessories, and finally Terminal. Ubuntu users typically take the ability to run the Sudo command for granted. How to Recover a Damaged Memory Card in Ubuntu. Select the medium through your motherboard's boot options. I can't get into Ubuntu (gui). Example: wsl -s Ubuntu would set my default distribution to Ubuntu. 04 LTS: In the GRUB Rescue command line interface, you can list the hard drives and partitions you have installed with the following command:. That should activate your first ethernet adapter and run dhclient to get it an address via DHCP. For Ubuntu Server, use the command below to edit the Grub configuration file: sudo nano /etc/default/grub. Ubuntu GNOME 16. How to repair Grub Boot Loader on Ubuntu or restore or reinstall Grub on Ubuntu. Note: There was a small drawback however after using bcdboot - the "Repair your computer" in advanced boot options on F8 key for the repaired loader (and boot menu entry) was missing but that was easy to solve with just two commands on command prompt (from a running Windows 8 VHD system in my case):. The symptom is that after entering the username and password in the login screen, they are unable to get in. To Repair GRUB2 Instend of Windows Boot Manager. This is equivalent to the -As options. Skip to main content. TestDisk is a free and open source data recovery software tool designed to recover lost partition and unerase deleted files. This article will describe how locales (language settings) can be configured for Ubuntu from the command line. 1 (Data Recovery) is available via Deb Package for Ubuntu and Linux Mint Systems. If you pass the listnodes command without a node id, then the RPC will return information of ALL the nodes in your view. It is somewhat similar to MS Windows's "System restore" option. Major change that anybody who has ever used Ubuntu, will notice the new Desktop Environment. Please see the release announcement for more information. Webmin has been tested on all regular Debian releases, Ubuntu Linux, and derivatives like Xandros and APLINUX. Ubuntu-Rescue-Remix provides a Free-Libre Open-Source data recovery software toolkit based on Ubuntu. 5 (Ubuntu 1:1. Once Boot Repair analyzes the system, the respective. Ubuntu is one of the widely used desktop operating system in the open source world. This is a popular tool in the Ubuntu community; it will install or re-install GRUB 2 and automatically repair some common configuration problems. We have a guide to reinstalling the GRUB2 boot loader on Ubuntu, either with a graphical Boot Repair tool or by using standard Linux terminal commands. First one is to chroot into Ubuntu installation partition. It allows you to choose which operating system or specific kernel to boot into. Ubuntu users typically take the ability to run the Sudo command for granted. It is also possible to use the grub command to install the boot loader, but not the Grub files in /boot/grub. stats() in MongoDB. 10, but by mistake I shut offed my laptop in between. However, it is disabled by default. Most IT professionals prefer to use a Command Line Interface (CLI) server, because it is safer and less prone to hacking. mysqlcheck - a command line client to check, repair, and optimize tables. It is also possible to use the grub command to install the boot loader, but not the Grub files in /boot/grub. Booting into Ubuntu live USB. Sponsored Link run the following commands from your terminal. Co-authored by wikiHow's Content Management Team carefully monitors the work from Enter the following command to. I was looking at the APT-How To. If you run into issues, or if you want support, training or architecture design consulting, please contact Canonical. How to run the native Ubuntu desktop on Windows 10. 04 using the apt package manager. That means if you are booting from the live installation environment, you need to be inside the chroot when running grub-install. Since, I dual boot Windows 8. The below mentioned process was followed on Ubuntu 16. How to repair Ubuntu if it won't boot. You can then remove the CD or USB device and continue to do your work from system memory. Don't worry, there are ways to address these types of issues. The project is open source. If you are using ubuntu linux use the following command. Open a terminal window and type the command sudo fsck. Since fixing sudo involves editing system files, and you would otherwise need sudo to do so, you'll have to boot into recovery mode to gain root (system-wide) access in order to repair sudo. Via command lines. The Ubuntu MySQL client can install as a stand-alone command-line tool, for example, you can install mysql server on one computer and the client package on another computer running Ubuntu operating system. ) If in doubt and there's a. mongo This will connect you to running MongoDB instance. If you install Windows operating system after you’ve installed a Linux distribution such as Ubuntu, you won’t be able to boot into your Linux operating system. How to run the native Ubuntu desktop on Windows 10. I started upgrade to 8. Solve difficult problems. [email protected]:~# sudo mount /dev/sdaX /mnt replace X with your drive number on which Ubuntu | Kali (Linux OS) Installed Installing grub needs access of some directories, so we need to bind them one by one using command line for detecting previously installed operating system. If I remember correctly, there is one version Ubuntu-Secure-Remix (link is provided on boot-repair page) , which has following functionalities. For more complex commands it is often both advisable and easier to write a simple shell script and use the '-c' option to execute it as part of respinning. sudo apt-get update –fix-missing. After trying. Ubuntu Linux provides OpenSSH which is a freely available version of the Secure Shell (SSH) and is OpenBSD Secure Shell in its repositories, which is a suite of security-related network-level utilities based on the SSH protocol. 04, even non-LTS releases like Ubuntu 17. vmstat ( Virtual Memory Statistics ) vmstat is a Linux command utility used to analyze and collect data about the system’s disks,CPU activity, memory, threads, swap, paging, block IO, CPU scheduling, system processes and many other parameters in real time. virt-convert is a command line tool for converting OVF and VMX VM configurations to run with libvirt. How to repair GRUB. stats() in MongoDB. In many cases this will be due to the /boot drive becoming 100% full because many updates have been made to the kernel. Introduzione. 04 Linux is to right. CD images for Ubuntu 12. 04 (Precise Pangolin) Linux Mint 13 ; Method 1 If you are able to reach the login screen, press CTRL+ALT+F2 to enter CLI mode, then enter your login credentials and kill Xserver with this command: sudo service lightdm stop Uninstall now the current AMD driver with these commands:. If you want to change it, use the following command. This wikiHow teaches you how to recover a broken Ubuntu system. The simplest way to fix the problem is to set mpicc to OpenMPI is by running the following command in a terminal prompt: sudo update-alternatives --set mpi /usr/lib/openmpi/include The. GRUB is what makes dual booting a PC with Windows and a Linux distribution such as Ubuntu possible. In the recovery period, be careful, as they can be asked the questions and instructions with terminal commands that should be run to continue the restore process. 1 (Data Recovery) is available via Deb Package for Ubuntu and Linux Mint Systems. Because on Linux, you usually should use terminal commands instead of just clicking the launcher icon (as you did on Windows). If you just want a console for temporary use, press Ctrl+Alt+F1 on keyboard will switch your desktop to tty1. In Ubuntu 14. 04, I have listed out a few recommended steps that you can follow to get started with it. Easy-to-use (repair in 1 click ! ) Free (GPL open-source license) Helpful (Boot-Info summary to get help by email or on your favorite forum) Safe (automatic backups) Can recover access to Windows (XP, Vista, Seven). There is a similar article for Debian: Perl warning Setting locale failed in Debian. In all modern Linux operating. XFS was created at Silicon Graphics, Inc. The symptom is that after entering the username and password in the login screen, they are unable to get in. If you run into issues, or if you want support, training or architecture design consulting, please contact Canonical. To report a security vulnerability in an Ubuntu package, please contact the Ubuntu Security Team. It's still a beta release, so there are some rough edges, but it provides easy access to various tools using its wizard, Rescapp. Step 2 - Install TestDisk in the live-session. If that works successfully, you might be able to do repair your installation by running: sudo aptitude install ubuntu-desktop That command will install the packages which are included in a base Ubuntu install. Performing the following commands will try and fix any broken packages currently installed on your system: sudo apt-get update --fix-missing sudo apt-get install -f (the -f option is short for fix-broken. YeoWorks Ubuntu Solutions provides a one click solution to many commonly faced Ubuntu problems. That should activate your first ethernet adapter and run dhclient to get it an address via DHCP. Repair Ubuntu running in a Virtual Machine Bruce Fulton Demonstrated with a VM running Ubuntu Server 10. Ubuntu, like many other non-Windows operating systems, does support dual booting. It works by creating a backup of a Ubuntu system in its current state, so that in any case something goes wrong, you can undo all changes and restore the system with this backup. To install it, from the steps below: 1. When this happens, you can repair the damaged file system and return it to its normal state using the Ubuntu boot CD. The below mentioned process was followed on Ubuntu 16. In some cases, we don't get system restart button in GUI but we still can restart the remote server using the command line. Do not assume that Ubuntu GNOME will do it for you automatically. It allows updating Ubuntu, Gnomes 3 installation and uninstallation, Firefox 4 flash issue fix and much more. Cron is driven by a crontab (cron table) file, a configuration file that specifies shell commands to run periodically on a given schedule. Sometimes, in a distribution like Linux Mint, you might need to change $(lsb_release -cs) to your parent Ubuntu distribution. 04 LTS operating system that I have installed. Ubuntu GNOME 17. fsck "fsck" is used to check and optionally repair one or more of your Linux filesystems. We are building Debian packages for several Ubuntu platforms, listed below. For Linux users, there is an open source tool called Systemback, which backs up the system and restores it to its previous state. If that doesn't work you can boot Ubuntu in recovery mode and repair broken packages. I checked everywhere but didn't find the way to have and use it. How to Resize Partitions with the Ubuntu or GParted Live CD 319. MySQL Repair Table and Repair Database Guide. Via command lines. You are then logged in as root (the superuser) and can repair your system using command line tools. Tested on: Ubuntu 13. There are several other advanced uses of Chroot like testing unstable applications, creating an environment with dependency control etc. This is a popular tool in the Ubuntu community; it will install or re-install GRUB 2 and automatically repair some common configuration problems. In a few simple steps, we will explain, how to automate your system tasks on Ubuntu, using the crontab in Ubuntu. Yannubuntu also has Hybride OS which has boot-repair, grub customizer installed by default. Step 2 - Install TestDisk in the live-session. By using our services, you agree to our use of cookies. The above command will pick up a ton of dependencies and ask you to okay the. It allows updating Ubuntu, Gnomes 3 installation and uninstallation, Firefox 4 flash issue fix and much more. grub rescue> 1. Repair Ubuntu running in a Virtual Machine Bruce Fulton Demonstrated with a VM running Ubuntu Server 10. In this guide, you will discover a number of different ways to open an application using Ubuntu. Once Ubuntu boots you'll want to install grub onto Ubuntu's drives and possibly restore the bootloader of another operating system if Ubuntu stepped on it. alias Create an alias • apropos Search Help manual pages (man -k) apt-get Search for and install software packages (Debian/Ubuntu) aptitude Search for and install software packages (Debian/Ubuntu) aspell Spell Checker awk Find and Replace text, database sort/validate/index b basename Strip directory and suffix from filenames base32. Earlier, we published a detailed post on the utility, and how to install it on Ubuntu, Linux Mint, and elementary OS. Repair the Boot Record. fsck (file system consistency check) — check and repair a Linux file system. Then type the following commands in the terminal mkdir 3. They're most commonly a cause of unmet dependencies, especially when they're used to upgrade an existing package from the Ubuntu repository. 04 linux server. How to Get Familiar With Ubuntu Commands. I have had it running fine for a while. Do not assume that Ubuntu GNOME will do it for you automatically. When this happens, you can repair the damaged file system and return it to its normal state using the Ubuntu boot CD. In a few simple steps, we will explain, how to automate your system tasks on Ubuntu, using the crontab in Ubuntu. Step-by-step process to Remove Ubuntu From Dual Boot Windows 10:-. Another easy way how to open Terminal on Ubuntu Bionic Beaver 18. 04, and I'd like to see disk IO stats. You can find out more from the Ubuntu MATE Raspberry Pi page and the Ubuntu MATE UMPC page. How to Repair a Corrupt MBR and boot into Linux Ubuntu Live CD and so on. But, I don’t want to do that. We can pull that off like so: cd /d v: EFI Microsoft Boot bootrec /fixboot The CD command tells the command line interpreter to change the directory to the volume label that has the EFI boot record. I started upgrade to 8. This information is collected via the gossip network. I'm a bit new to ubuntu. mkvtoolnix-gui Here's an example using mkvpropedit to change a movie's title:. If you want to access their source code you can use the apt-get source command. 04, and I'd like to see disk IO stats. We have a guide to reinstalling the GRUB2 boot loader on Ubuntu, either with a graphical Boot Repair tool or by using standard Linux terminal commands. the rm command but i cant. ) create a boot info summary (to provide input for when asking for help in forums. That should activate your first ethernet adapter and run dhclient to get it an address via DHCP. Linux is free, open source and a great operating system, but it will not suit each one of us. par2 This tells par2 to verify and if possible repair any damaged or missing files. They’re most commonly a cause of unmet dependencies, especially when they’re used to upgrade an existing package from the Ubuntu repository. sudo apt-get install -f. Step One: Install Apache. The benefit of the above command is that it uses the. When they do, MySQL includes several tools that you can use to check and repair database tables. In this tutorial, we will discuss how you can do this. @fmonegaglia It depends. Step 1 - Boot on a liveCD or liveUSB. Open up a terminal window and issue the command: sudo apt-get install ubuntu-gnome-desktop. Having a pen drive is ideal here, as you can use it easily. These notices are also posted to the ubuntu-security-announce mailing list (list archive). Before jumping into the command line, you have to make sure about the specific broken package. The Boot Repair tool also deserves mention. These are the Ubuntu security notices that affect the current supported releases of Ubuntu. When I restarted it, Windows failed to load and the automatic repair loop kicked in. If you want the command to be started, and the script waits for it to finish before continuing to the next command on the script, then no &. In this article, we will explain how to recover your accidentally lost files on Ubuntu through the TestDisk utility.