The whole of /srv is one filesystem. A 4 GiB image at /srv/iso/debian.iso must also be reachable as /srv/pub/debian.iso, must consume no additional disk space, and the second name must keep working even if /srv/iso/debian.iso is later removed. Which command satisfies all three requirements?
LPIC-1 Exam 101-500, objective 104. Devices, Linux filesystems, filesystem hierarchy standard medium
Machine-checked — no person has signed for it. This question was read against the source cited below by an automated pass, which found no contradiction. That is a weaker claim than it sounds: the same kind of process wrote the question, so it can confirm its own mistake.
Treat it as a good draft rather than as settled fact, and read the source below before you rely on it. It is not used in mock exams here — only questions a person has signed for are.
How these questions are written — where each question comes from, what the verification ledger records, and what happens when one is found wrong.
The options
Correct ln /srv/iso/debian.iso /srv/pub/debian.iso
Correct. A hard link adds a directory entry to the existing inode: no data is duplicated, and the inode survives until the last name referring to it is removed.
Not correct ln -s /srv/iso/debian.iso /srv/pub/debian.iso
Wrong on the last requirement. A symbolic link costs almost no space, but it records a path; delete /srv/iso/debian.iso and the link dangles.
Not correct cp /srv/iso/debian.iso /srv/pub/debian.iso
Wrong on the space requirement. cp allocates a second, independent inode and writes another 4 GiB of blocks.
Not correct mv /srv/iso/debian.iso /srv/pub/debian.iso
Wrong. Within one filesystem mv only renames the directory entry, so you end up with one name rather than two.
Why
This is the practical difference between copying and linking. A copy duplicates the data and produces a file whose later changes are independent; a hard link produces another name for the identical inode, so the content is shared and the link count rises. Unlinking a name only decrements that count, and the blocks are freed when the count reaches zero and no process still holds the file open. Hard links are confined to a single filesystem and, on Linux, may not be made to directories.
Where this comes from
- Cited
- manual page ln(1)
Practise this
Reading one question is not practice. The trainer will draw a short set from objective 104 and space the ones you get wrong.
More questions on this objective
- A new disk /dev/sdb has no partition table at all. Which command writes an empty GPT partition table onto it without dropping you into an interactive editor? machine-checked
- You need the partition /dev/sdc1 on a USB stick to carry a FAT32 filesystem so that Windows machines can read and write it. Which command creates it? machine-checked
- You have just run `mkswap /dev/sdb2`. Which command makes the kernel start using that swap area immediately, without a reboot? machine-checked
- Why is it dangerous to run e2fsck against an ext4 filesystem that is currently mounted read-write? machine-checked
- On an ext4 filesystem at /dev/sda1 you want an automatic check to be forced after every 30 mounts. Which command sets that? machine-checked
- `df -h /var` reports the filesystem 100% full, but `du -sh /var` accounts for only about half that space. Nothing is hidden under a mount point. What is the most likely explanation? machine-checked
All questions on Devices, Linux filesystems, filesystem hierarchy standard