Score:2

Ubuntu

apt-cache show - show single field of a package

Mario Palumbo

7/7/24, 3:42 PM

As for:

$ dpkg -f <deb-file> <field>

there is something that likewise:

$ apt-cache show <package> <field>

returns me a field of a package?

For example, assuming I have discord already installed and its .deb archive in the current directory, I run the commands:

$ dpkg -f ./discord.deb Version
$ apt-cache show discord Version

Outputs I'd like:

0.0.27
0.0.27

Actual output:

0.0.27
... # discord package unwanted long output
N: Unable to locate package Version

I'd like a solution that makes use of the apt-cache or dpkg command itself.
In the absence of such a solution, then I accept the usual parser.

How do I solve?

EDIT 1:

I only want to display the installed version of a package.

2 + 1

package-management

apt

bash

22.04

Raffa

7/8/24, 9:36 AM

`apt-cache show` takes only package-names as arguments ... So, `Version` will be looked up as a package.

Score:2

Ubuntu

Artur Meinild

7/7/24, 3:56 PM

To show only the installed version of a package: (and subsequently, this only works for installed packages)

dpkg-query --showformat='${Version}' --show <package>

To include a line break, just include a newline in the format string:

dpkg-query --showformat='${Version}\n' --show <package>

+ 4

Raffa

7/8/24, 9:34 AM

`--showformat=` accepts "\" as an escape character ... So, `--showformat='${Version}\n'` should work to feed a newline after the output.

Mario Palumbo

7/10/24, 10:58 AM

Yes, you are right, "apt-cache show" would also show the version of a package not yet installed, which is not what I want. Thanks for pointing it out to me.

Mario Palumbo

7/10/24, 11:02 AM

This is the solution I want, thank you.

Mario Palumbo

7/10/24, 11:05 AM

For line break also this `dpkg-query -f '${Version}\n' -W <package>` is good.

Score:2

Ubuntu

Marco

7/7/24, 3:56 PM

This one-liner extracts the version of a package:

apt-cache show packagename | awk '/^Version:/{print $2;}'

+ 1

Raffa

7/8/24, 9:41 AM

Some packages might show more than once in the output like e.g. apt and dpkg ... So, to print only the first reported version an `exit` action might be added like e.g. `apt-cache show apt | awk '/^Version:/{print $2; exit}'`

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: apt-cache show <package> <field> - show single field of a package

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