How can I tell what date Ubuntu was installed?

Solution 1:

You can check the installer logs and dates at:

/var/log/installer

A quick way to find the date through the command line would be by running:

ls -lt /var/log/installer

That lists in reverse chronological order so the oldest file is at the bottom of the list.

Solution 2:

If you use ext2/ext3/ext4 and formatted the disk when you installed you can do this nifty trick.

sudo dumpe2fs /dev/sda1 | grep 'Filesystem created:'

You might have to change the /dev/sda1 to reflect your setup.

Relaying on the date of files, even the "creation time" (mtime) can give errors since upgrading packages might have replaced the file and made a new "creation time".

Similar tools and info might be available on other file systems as well, but I don't know of them.