Before and after Figure 2.6, you're talking about filtering out .bck files, but Fig 2.6, which shows how filtering actually works, is showing files with a trailing tilde instead. Would think it best, for continuity with the surrounding text, to adjust Fig 2.6 to convert "first.txt~" and "second.txt~" to "first.bck" and "second.bck", so that it's crystal clear why a .bck filter would remove those two files.
Before and after Figure 2.6, you're talking about filtering out .bck files, but Fig 2.6, which shows how filtering actually works, is showing files with a trailing tilde instead. Would think it best, for continuity with the surrounding text, to adjust Fig 2.6 to convert "first.txt~" and "second.txt~" to "first.bck" and "second.bck", so that it's crystal clear why a .bck filter would remove those two files.