Thought the specifics are fairly useless, Unless you want to find out exactly what changes were made to the system on a specific day and time, I felt the steps I went through to discover this information were worth documenting:
strace -e trace=open -f -o usc software-center to get a list of all the files opened by the software center. Then I filtered it like this.
cat usc| grep -oP '(?<=open\(").*(?=",)' |egrep -v '\.(so\.([0-9]|cache)|so|pyc|mo|py|png|svg)$'|egrep -v '/usr/lib/(python2.7|x86|girepo)'| egrep -v '/usr/share/(icons|themes)' |egrep -v '/etc/fonts'|egrep -v '(screenshots|reviews)\.ubuntu\.com' |egrep -v fontconfig |sort -u
to eliminate all the files didn't contain data files.
Among these I found the interesting looking looking file:
~/.cache/software-center/apthistory.p It looked like a python pickle file when I opened it. trying to load the file I got the error that
softwarecenter.db.history_impl.apthistory was not imported. I ran the following command to look for python files that ere opened and had "softwarecenter" in their path
$cat usc| grep -oP '(?<=open\(").*(?=",)' |grep softwarecenter
and got a whole bunch of filenames including
/usr/share/software-center/softwarecenter/db/history_impl/apthistory.so I wrote the following script to read and process file:
with open(os.path.expanduser('~/.cache/software-center/apthistory.p')) as IFile:
print "earliest apt transaction started on:",hist[-1].start_date
for PackageStr in hist[-1].install:
for PackageStr in hist[-1].upgrade:
I found the necessary attributes by looking up the class of which hist was an instance of:
help(softwarecenter.db.history_impl.apthistory.AptTransaction). This lead me to the parent class
help( softwarecenter.db.history.Transaction) from where I figured out how to use it.
sudo apt-get installed stuff appears here.