Suppose you want to change just one or a few attributes to the same value for all lists in an installation. You can do the following?

Put the desired setting(s) in a file. For this example, assume we want to set max_days_to_hold to 5 for all lists. Put this line

max_days_to_hold = 5

in a file.

For an overview of all settings, run

~mailman/bin/config_list -o - LISTNAME

for some LISTNAME.

Then run the following script

cd ~mailman
for list in `bin/list_lists --bare` ; do
bin/config_list -i /path/to/above/file $list
done

See

bin/config_list --help

for more information.