On Mon, 13 Oct 2025, The Wanderer wrote: > On 2025-10-13 at 10:34, [email protected] wrote: > >> On Mon, 13 Oct 2025, Greg Wooledge wrote: >> >>> On Mon, Oct 13, 2025 at 13:07:37 +0000, [email protected] wrote: > >>>> i've read that several times >>>> i don't see anything that tells me the details of how apt is performing >>>> the search >>> >>> I don't understand what you're asking. >>> >>> ~e means the rest of it is a regex (regular expression) which is matched >>> against the source package name. (It would be nice if it specified >>> which flavor of regex it's using, because there are many.) >>> >>> ^science is a regex that matches any string/line beginning with the >>> substring "science". (At least in BRE, ERE and PCRE flavors.) >>> >>> So, putting it together, it should match all packages whose source package >>> name begins with "science". >>> >>> When I run it on my system, I get the following result: >>> >>> hobbit:~$ apt list '~e^science' >>> ESC[32mlibjs-sciencejsESC[0m/stable,stable 1.9.3+dfsg-4 all >>> >>> This package is not installed, so it seems it's looking at available >>> packages. This is the package it's referring to: >>> >>> hobbit:~$ apt-cache show libjs-sciencejs >>> Package: libjs-sciencejs >>> Source: science.js >>> Version: 1.9.3+dfsg-4 >>> [...] >>> >>> As you can see, its source package name is "science.js" which does in >>> fact begin with "science". So, it looks like it's working as documented. >> >> apt list ~e^science is an example >> not what i'm interested in >> i'm interested in the details of how apt go about doing whatever it's doing > > Well, what details are you interested in getting? > > Do you want to know what files, or other data sources, it looks at? What > parts of those files it matches against? What methods it uses to search > through them? How it determines what does and does not count as a match? > Something else? (Multiple somethings else?) > > For some of those, the answers can be found within the information > you've already been given; for example, the "how it determines what does > and does not count as a match" is answered by "regex", which is to say > "regular expression". Regular expressions are a topic all on their own, > which is amply documented in many places, one of which you've been > pointed to elsewhere in this thread. > > For most of the rest of the things I suggested as ideas of what might be > the details you're interested in getting, the only way you're going to > find the answers is to look at the source code of apt. apt itself does > not appear (at least not at a simple skim) to include debug or verbose > output options, certainly not ones so extensive as to let you follow > along step-by-step with what it's doing. > > In theory you could alternately (or also) run the program under strace > or possibly a debugger, and use that to look at what functions it's > calling and with what arguments and so forth, and use that to help > inform your understanding of what's being done when the program runs. > But there is only so much utility to be found in doing that without also > referencing the source code, so you'd probably be better off going > straight for that option instead. > > The source code for apt can be obtained by, among other methods, running > 'apt source apt'; this is documented in the man page for apt-get, which > is pointed to by the man page for apt. That works the same way with any > package name; you can e.g. run 'apt source dpkg' or 'apt source > xserver-xorg-core' or 'apt source xorg-server', and each of those will > download and set up a source-package directory for the specified package. > > (The latter two, if I'm not mistaken, will in fact fetch and set up the > exact same source-package directory; the first of them specifies the > name of a binary package, and the latter the name of the source package > from which that binary package was built.) > > If none of that helps you find out how to find out what you're wanting > to know, then I'm afraid you're going to have to figure out some way to > be more clear about exactly what it is that you're wanting to know, > because the way you've been explaining it so far isn't conveying enough > information for us to be able to figure out what sort of answer would > satisfy your interest. >
i guess that about covers it from what i've read apt does not provide debug that let you look under the covers it's read the code or nothing thanks
