There are 2 fields which we can, the options (which we will look at in detail later) and the filesystems. The filesystems can be a device, partition, mount point, or anything else.<\/p>\n
Options used with the fsck command<\/h3>\n
The fsck command needs to be run with superuser privileges (sudo) or root. Let us look at the options we use along with fsck.<\/p>\n
1. -A<\/h4>\n
This option checks all the filesystems<\/p>\n
2. -a<\/h4>\n
This option tries to repair filesystems errors automatically. There ill be no prompts.<\/p>\n
3. -C<\/h4>\n
This option shows the progress bar<\/p>\n
4. -f<\/h4>\n
This option forces fsck to check a file system. Using this option memes fsck check even a clean filesystem<\/p>\n
5. -l<\/h4>\n
This option locks the device to guarantee no other program will try to use the partition during the check.<\/p>\n
6. -M<\/h4>\n
This option does not check the mounted filesystems<\/p>\n
7. -N<\/h4>\n
This option only shows what would be done and no actual changes are made.<\/p>\n
8. -P<\/h4>\n
This option checks the filesystems and root parallelly<\/p>\n
9. -R<\/h4>\n
This option does not check the root filesystem.<\/p>\n
10. -r<\/h4>\n
This option provides statistics for each device that is being checked.<\/p>\n
11. -T<\/h4>\n
This option does not show the title.<\/p>\n
12. -t<\/h4>\n
This option exclusively specifies the filesystem types to be checked. You can specify by separating them with a comma.<\/p>\n
13. -y<\/h4>\n
This option tries to repair the filesystem type to check with fsck<\/p>\n
14. -V<\/h4>\n
This option provides a description of what is being done.<\/p>\n
Meaning of fsck exit codes<\/h3>\n
After running fsck, it will return an exit code, it is important to know the meaning of these exit codes:<\/p>\n
a. 0<\/h4>\n
This exit code means that there are no errors.<\/p>\n
b. 1<\/h4>\n
This exit code means that there were errors and fsck corrected them.<\/p>\n
c. 2<\/h4>\n
This exit code means that the system should be rebooted.<\/p>\n
d. 4<\/h4>\n
This exit code means that the errors in the filesystem were left uncorrected.<\/p>\n
e. 8<\/h4>\n
This exit code means that there was an operational error.<\/p>\n
f. 16<\/h4>\n
This exit code means that there is an error either in the usage or syntax.<\/p>\n
g. 32<\/h4>\n
This exit code means that the fsck checking has been canceled by your request.<\/p>\n
h. 128<\/h4>\n
This exit code means that there is a shared library error.<\/p>\n
You can look up these options or exit code meanings anytime by typing \u201cman fsck\u201d in the terminal:<\/p>\n
Running Linux fsck command on reboot (recovery mode)<\/h3>\n
Now that you know the syntax, options and how to read the exit code, let us see the steps to run fsck command on reboot:<\/p>\n
1: To reboot your Linux system, type reboot in the terminal, or you can just do it the lengthy traditional way.<\/p>\n
2: While your system is rebooting, press and hold down the \u201cshift\u201d key to open up the grub menu. In the grub menu, select the \u201cadvanced options for ubuntu\u201d option as shown in the figure:<\/p>\n
3. On the next screen select the \u201cUbuntu, with Linux 5.12.0-39-generic (recovery mode)\u201d option as shown:<\/p>\n 4. Next, the recovery menu will open, where you will find different options like grub, clean, dpkg, root, network, system summary, and many more<\/p>\n In the recovery menu navigate to the \u201cfsck\u201d option and press enter.<\/p>\n A pop-up will ask you to confirm if you want to continue with fsck checking all filesystems. Press yes.<\/p>\n On successful running of fcsk, you will see this screen:<\/p>\n 5. After successful checking, it will take you back to the previous screen, click on resume normal boot<\/p>\n And press on ok in the next popup to exit recovery mode and resume normal boot.<\/p>\n And done! You have successfully checked your files systems during your systems reboot from the recovery menu<\/p>\n Before we start checking, we must first locate the disc you want to scan. You can do so by listing the filesystems disks with the \u201cdf\u201d command.<\/p>\n For the sake of an example, I am going to take the filesystem \u201c\/dev\/sda1\u201d. You can take any filesystem you want, just make sure there are not many with the same name. If you wish to check how many filesystems are there with that name, you can do so by using the command \u201csudo parted <filestystem name> \u2018print\u2019 \u201d<\/p>\n <\/p>\n <\/p>\n sda is how Linux refers to the first SCSI disk, if you have 2, the second one would be called sdb<\/p>\n If you run fsck directly, you will get an error message saying that it cannot continue checking and it is aborting.<\/p>\n This happens because you did not unmount the disk, To unmount a disk use the command \u201csudo umount <disk name>\u201d<\/p>\n After unmounting the disc, try to run fsck again and you will not find any errors.<\/p>\n <\/p>\n After running fsck, mount back the disk you have unmounted, you can mount a disk by using the command \u201cmount <disk name>\u201d<\/p>\n Before actually performing a proper check, let us do a dry run to ensure everything is in place.<\/p>\n We can perform a dry run by using the command \u201csudo fsck -N <dsik>\u201d<\/p>\n The option \u201c-N\u201d as we discussed above will only print what is going to happen, and not actually do anything.<\/p>\n If you use the command \u201csudo fsck -n <file system name>\u201d, fsck will print out the error message, if there is something wrong with the file system, but it will not repair it.<\/p>\n If you wish to perform a search only on unmounted filesystems and avoid mounted file systems, you can do so by using the command \u201csudo fsck -M <file system name>\u201d<\/p>\n If you observe the above snippet, the command did not run when \u201c\/dev\/sda1\u201d was mounted but checked when it was unmounted.<\/p>\n If you want fsck to fix errors automatically without prompting you to press y or n, you can use the command \u201csudo fsck -y <filesystem name>\u201d<\/p>\n This command says yes to \u2018try to fix all errors\u2019 without being prompted every single time.<\/p>\n Here forcing means to run a check even on a clean filesystem. By default, if you try performing an fsck check on a clean device, the tool skips the filesystem check.<\/p>\n Hence to perform a force fsck check on a filesystem, you use the command \u201csudo fsck -f <filesystem name>\u201d<\/p>\n This command will scan the file and performs all 5 checks to search for corruption in the filesystem, even though it is a clean file.<\/p>\n To perform an fsck check on all the file systems, use the command<\/p>\n The option \u201c-A\u201d searches all the filesystems, the option \u201c-R\u201d unmounts all the filesystems, and the flag \u201c-y\u201d is to avoid fsck printing us every time.<\/p>\n![\"selecting](\"https:\/\/data-flair.training\/blogs\/wp-content\/uploads\/sites\/2\/2022\/06\/selecting-advanced-options-in-GRUB-menu.webp\")
<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\nChecking and repairing filesystems manually<\/h3>\n
Finding the disk to be checked<\/h4>\n
<\/a><\/p>\n<\/a><\/p>\nUnmounting a disk<\/h4>\n
<\/a><\/p>\n<\/a><\/p>\nPerforming a dry run with fsck<\/h4>\n
Skip repair but print error output<\/h4>\n
<\/a><\/p>\nSkipping search on mounted filesystems<\/h4>\n
<\/a><\/p>\nFix errors automatically<\/h4>\n
Forcing fsck to check a filesystem<\/h4>\n
<\/a><\/p>\nRunning fsck on all filesystems at once<\/h4>\n
\u201csudo fsck -AR -y\u201d<\/pre>\n