Merging pdfs with pdftk

As discussed on Noel O'Blog's website, you can merge pdfs with the program pdftk.

For example, to merge three pdfs MolBiolCellCh1_fig1.pdf, MolBiolCellCh1_fig2.pdf and MolBiolCellCh1_fig3.pdf, you can type:
% pdftk A=MolBiolCellCh1_fig1.pdf B=MolBiolCellCh1_fig2.pdf C=MolBiolCellCh1_fig3.pdf  output MolBiolCellCh1_1_figs.pdf

This makes one output pdf, MolBiolCellCh1_1_figs.pdf, that has the three other pdfs merged together in order.