Before removing a library package you want to know which other packages in the archive would break because they depend on it. Which command lists them?
LPIC-1 Exam 101-500, objective 102. Linux installation and package management medium
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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 apt-cache rdepends libfoo1
Correct. rdepends prints the reverse dependencies, that is every package in the index that declares a dependency on the named package.
Not correct apt-cache depends libfoo1
Wrong direction. depends lists what libfoo1 itself requires, not what requires libfoo1.
Not correct apt-cache pkgnames libfoo1
Wrong. pkgnames prints the names of all known packages, optionally filtered by a prefix; it says nothing about relationships.
Not correct dpkg -L libfoo1
Wrong. -L lists the files the installed package owns, which is unrelated to dependency relationships.
Why
apt-cache queries the package index that apt-get update downloaded, so it can answer questions about packages whether or not they are installed. depends and rdepends are mirror images: forward dependencies of a package, and packages depending on it. For the raw record including the Depends and Conflicts fields use apt-cache show, and for the available versions and their priorities apt-cache policy.
Where this comes from
- Cited
- manual page apt-cache(8)
Practise this
Reading one question is not practice. The trainer will draw a short set from objective 102 and space the ones you get wrong.
More questions on this objective
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