Command to list recently installed packages that were installed via any method (apt-get, Software Center et al.):

grep " install " /var/log/dpkg.log

Example output:

2010-12-08 15:48:14 install python-testtools <none> 0.9.2-1
2010-12-08 15:48:16 install quickly-widgets <none> 10.09
2010-12-08 22:21:31 install libobasis3.3-sdk <none> 3.3.0-17
2010-12-09 12:00:24 install mc <none> 3:4.7.0.6-1
2010-12-09 23:32:06 install oggconvert <none> 0.3.3-1ubuntu1
2010-12-09 23:34:50 install mpg123 <none> 1.12.1-3ubuntu1
2010-12-09 23:34:52 install dir2ogg <none> 0.11.8-1
2010-12-09 23:34:53 install faad <none> 2.7-4
2010-12-09 23:34:54 install wavpack <none> 4.60.1-1
2010-12-10 11:53:00 install playonlinux <none> 3.8.6

You could run this command to list only the recently installed package names,

awk '$3~/^install$/ {print $4;}' /var/log/dpkg.log

Command to list history of apt-get (NOTE: this doesn't list dependencies installed, it simply lists previous apt-get commands that were run):

grep " install " /var/log/apt/history.log

Example output:

Commandline: apt-get install libindicate-doc
Commandline: apt-get install googlecl
Commandline: apt-get --reinstall install ttf-mscorefonts-installer
Commandline: apt-get install valac libvala-0.10-dev
Commandline: apt-get install libgtksourceview-dev
Commandline: apt-get install python-sphinx
Commandline: apt-get install python-epydoc
Commandline: apt-get install quickly-widgets
Commandline: apt-get install libreoffice3* libobasis3.3*
Commandline: apt-get install mc

To see also older packages sorted by time of installation:

grep " install " /var/log/dpkg.log.1 /var/log/dpkg.log

And for packages installed very long time ago:

gunzip -c `ls -tr /var/log/dpkg.log.*.gz` | grep " install "

Ubuntu's Software Center shows whole history of all packages that were installed/upgraded/removed. Just click "History" at the bottom of the list at left.

The following trick answers Aleksandr Dubinsky's request to limit this to manually-installed packages:

comm -12 <(apt-mark showmanual | sort) <(grep " install " /var/log/dpkg.log | cut -d " " -sf4 | grep -o "^[^:]*" | sort)

• comm -12 lists lines common to two sorted files.
• <(command) expands to the name of a file containing the output of command.
• apt-mark showmanual lists manually installed packages; ie. those that should never be auto-removed.
• grep " install " /var/log/dpkg.log is taken from the accepted answer.

An alternative, showing more information, in chronological order, and accessing all available logs, is:

zcat -f /var/log/dpkg.log* | grep " install " | sort > /tmp/dpkg.log
grep -F "`comm -12 <(apt-mark showmanual | sort) <(cat /tmp/dpkg.log | cut -d " " -sf4 | grep -o "^[^:]*" | sort)`" /tmp/dpkg.log | grep \<none\>

grep \<none\> limits results to new installations. You could, for example, use grep to limit the search to a three-month period by adding grep 2016-0[567] to the first pipeline; it's very flexible.

All on one line; for command use

Select and print only the recently installed package-names, all on one line.

To do so, change the most-voted answer to:

cat /var/log/dpkg.log |awk '/ install / {printf "%s ",$4}'

This results in a single line of package names. Such a line can easily be added to a sudo apt-get purge command.

Example output

libgnome-media-profiles-3.0-0 gstreamer0.10-gconf gnome-media gnome-menus librest-0.7-0 libgoa-1.0-common libgoa-1.0-0 libwacom-common libwacom2 ubuntu-docs apg libgnome-control-center1 libgnomekbd-common libgnomekbd7 gnome-control-center-data gnome-icon-theme-symbolic gnome-settings-daemon ubuntu-system-service gnome-control-center gnome-online-accounts gnome-session-bin indicator-power mousetweaks

Listing packages one below another

By popular demand, here is slightly adapted version for listing the packages one below another:

cat /var/log/dpkg.log |awk '/ install / {printf "%s\n",$4}'

There is a package called wajig Check it out for the command line, it is the first thing I install now. Like aptitude, except that it works like you'd expect a command dispatcher to work. So really, it's not like aptitude. Commands below are just a small subset.

wajig help
Common JIG commands:

 update         Update the list of downloadable packages

 new            List packages that became available since last update
 newupgrades    List packages newly available for upgrading

 install        Install (or upgrade) one or more packages or .deb files
 remove         Remove one or more packages (see also purge)

 toupgrade      List packages with newer versions available for upgrading
 upgrade        Upgrade all of the installed packages or just those listed

 listfiles      List the files that are supplied by the named package
 listnames      List all known packages or those containing supplied string
 whatis         For each package named obtain a one line description
 whichpkg       Find the package that supplies the given command or file

Run 'wajig -v commands' for a complete list of commands.

Here is some shell to list dpkg installed files. (which should include all apt/aptitude/software center/synaptic installed packages)

grep -A 1 "Package: " /var/lib/dpkg/status | \
grep -B 1 -Ee "ok installed|half-installed|unpacked|half-configured|config-files" -Ee "^Essential:yes" | \
grep "Package:" | cut -d\  -f2

This does not include install time/date info. But may be useful in determining any differences in packages installed from os install to current.

In addition to DoR's answer, for those who prefer a GUI, there is a File -> History menu item in Synaptic.

The problem with viewing the installation history in Software Centre or Synaptic is that it's hard to copy/paste the contents into an email (e.g. when talking with tech support!). The alternative is to view the contents of the log files in /var/log/apt as root.