: creat "dc" and "bc" commands echo echo /bin/dc /usr/bin/bc chdir ../dc echo dc?.s ; as dc?.s ; mv -f a.out /bin/dc echo bc.c ; cc -O -s bc.c -ly ; mv -f a.out /usr/bin/bc echo lib.b ; cp lib.b /usr/lib/lib.b chmod 755 /bin/dc /usr/bin/bc chmod 644 /usr/lib/lib.b chown bin /bin/dc /usr/bin/bc /usr/lib/lib.b