Quick way to see if a list of packages exist in the repos or the AUR

Question

For a script I'm writing, I'd like to check if a list of packages actually exists in the enabled repos or in the AUR. Currently, I'm looping through all packages in the list and runing `pacman -Ss package_name`, but there are two problems with this. The first is  pacman can return multiple packages here, whereas I only want it to return the package that exactly matches `package_name`. I can fix this by using grep to find an exact match for the name. The second problem is that this method is very slow, but I want this to take no more than a second for about 100 packages. Is there a faster way I can figure out which packages actually exist?

Answer 1

gsingh93 wrote: The first is  pacman can return multiple packages here, whereas I only want it to return the package that exactly matches `package_name`. I can fix this by using grep to find an exact match for the name.
A better solution for that problem (as stated) is simply to use a proper regex.  The following returns only the single exact match:
pacman -Ss ^firefox$
gsingh93 wrote:The second problem is that this method is very slow, but I want this to take no more than a second for about 100 packages. Is there a faster way I can figure out which packages actually exist?
Then a much better approach would be something like the following:
comm -23 your_list_file <(pacman -Ssq | sort)
EDIT: I just tested the above command using a random selection of 100 package names from the repos with 40 of the modified (so as not to match) and then I ran the command through `time`:
real 0m0.283s
user 0m0.227s
sys 0m0.030s
If you want this to work for the AUR as well, we'd just need a list of all package names in the AUR.  This should be easy to get from the web-interface (standby I'll see if I can get it).  Then basically you'd do the following:
1) pacman -Ssq > pkglist
2) cmd_to_get_aur_names >> pkglist
3) comm -23 <(sort your_list_file) <(sort pkglist)
EDIT 2: I don't know of any efficient way to get a list of all AUR packages.  The best idea I had was to "simply" wget and parse this page: http://pkgbuild.com/git/aur-mirror.git/tree/ but at 26MB that takes well more than a second to download even on a good connection.  I suspect it will be far more efficient to get the `comm` output from above for a list of packages not in the repos, then for each of those search the aur as a fallback (with something like cower).
Last edited by Trilby (2014-12-24 21:38:08)