You know you want a Debian package for reading PDF files but you do not know any package's name. Which command searches package names and descriptions in the local package index for the word 'pdf'?
LPIC-1 Exam 101-500, objective 102. Linux installation and package management medium
Draft — not checked yet. This question was written from the published exam objectives and cites the clause it comes from, but nobody has yet read it against that clause and signed for it.
It is kept out of search results and out of mock exams until they have. Read the source below before you take the answer as settled.
The options
Not correct apt-get update pdf
Wrong. apt-get update refreshes the package index from the sources in /etc/apt/sources.list and takes no package argument; it never searches or installs.
Not correct apt-cache show pdf
Wrong. apt-cache show takes an exact package name and prints that package's record — version, dependencies, description. Given a word that is not a package name it simply reports that it cannot find it.
Not correct dpkg -S pdf
Wrong. dpkg -S searches the list of files belonging to packages that are already installed, to answer 'which package owns this file'. It cannot find packages you have not installed.
Correct apt-cache search pdf
Correct. apt-cache search matches the given terms against package names and their descriptions in the index and prints each matching name with its short description.
Why
Keep the apt-cache subcommands straight: 'search' takes a pattern and finds candidate packages, 'show' takes an exact name and prints its record, 'depends' and 'rdepends' walk the dependency graph, and 'policy' shows which versions are available and from where. All of them read the local index only, so they are only as current as your last 'apt-get update'. The equivalents under the newer apt front end are 'apt search' and 'apt show'.
Where this comes from
- Cited
- LPI exam objective 102.4
- What it says
- Find packages containing specific files or libraries, and query package information with apt-cache.
Practise this
Reading one question is not practice. The trainer will draw a set from objective 102 and space the ones you get wrong.