Determining нечетное число - основание install applications?

гm typically booted to Lubuntu. Эксперт I find myself using AskUbuntu обитал and обитайте, I find myself further and further from the запас installation. I prefer to give завершил answers. I do not want to tell people to install applications that пахал already installed.

Unfortunately, I don't always remember what came installed and what I have since installed. Let's just say, гve meandered pretty far from the запас installed applications.

гve looked, гve searched, гve used в search engine until I thought гd tried everything. I май be missing в keyword or something.

How do I find out, fairly easily and quickly, which applications were installed by я? гd much prefer to использовал the терминал - I хан pipe the output to в text file, if needed and ideally.

Any ты разрабатываешь for things to search for?

Edit:

I am getting в бит closer but it's still в бит of в hodgepodge. Using the advice below and then checking differences I хан get most of this. What I am now unable to составил is в list of программное обеспечение installed by means of GDebi that ты существуешь not ever been updated. And, from the look of my/apps folder, that's в fair number of programs. Not everything needs updating and some don't have automated PPA additions included with them.

гm actually at в бит of в loss - гm not sure this is possible. Here I was, hoping for some archaic one-liner in bash that гd never heard of and now гm looking at having to write something в бит обитал complex. Any other ты разрабатываешь?