Cannot grep apt-cache show output

Question

I have a list of packages and I want to know which packages are not available in the ubuntu repositories.

I type this command but it returns nothing :

$ apt-cache show vim TotO perl 2>&1 | grep "Unable to locate package"
$

It occurs in both Ubuntu 16.04 LTS and 18.04 LTS.

Can you help ?

What is the output of the apt-cache without grep ? Are there any "Unable to locate package" lines at all ? — Soren A, Oct 10 '20 at 13:50
@WilliamMartens It's unrelated because my grep search pattern doesn't start by a - The N0rbert's solution works fine. — SebMa, Oct 10 '20 at 14:04

score 6 · Accepted Answer · answered Oct 10 '20 at 13:52

As per apt-cache man-page

-q, --quiet
Quiet; produces output suitable for logging, omitting progress indicators. More q's will produce more quietness up to a maximum of 2. You can also use -q=# to set the quietness level, overriding the configuration file. Configuration Item: quiet.

you have to pass --quiet=0 to use apt-cache in scripts.

Use code below:

apt-cache --quiet=0 show vim TotO perl 2>&1 | grep "Unable to locate package"

or

apt-cache -q0 show vim TotO perl 2>&1 | grep "Unable to locate package"

Cannot grep apt-cache show output

1 Answers1