./configure --prefix= : We do this because shells should be installed in the /bin directory, not /usr/bin. cp tcsh.man /usr/share/man/man1/tcsh.1 :tcsh doesn't install its man-page correctly, so we do it manually. ln -s tcsh /bin/csh : The FHS states that if there is a C shell installed, there should be a symlink from /bin/csh to it. This creates that symlink.