If the commit occurred within the past 90 days, executing this command by date appears as follows:
bashgit show HEAD@{2013-02-25}:./fileInCurrentDirectory.txt
Note that HEAD@{2013-02-25} refers to the HEAD being at 2013-02-25 in this repository (using reflog), not the last commit before 2013-02-25 in the branch history.
This means that by default, this method only applies to history within the last 90 days. Otherwise, you need to execute the following:
bashgit show $(git rev-list -1 --before="2013-02-26" HEAD):./fileInCurrentDirectory.txt