Dpkg

commands

check if {packagename}  is installed :

dpkg -s <packagename>

dpkg-query  has a neater output , and accepts wild cards :

dpkg-query -l <packagename>

To find what package owns the command :

dpkg -S `which <command>`

to examine archive files

 dpkg --info   {.deb filename}
 dpkg-deb --info  {.deb filename}
 ```




find out which repository a package comes from

apt-cache policy
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