... Easily done with the following command.
ls *.po | xargs -t -n1 -I {} msgmerge -U --previous --add-location=file {} audacity.pot
Resulting files will have all the blanks to be filled in by the translators for
new messages.
--previous keeps the old msgids in comments, for which matches were only fuzzy,
as an aid to the translator.
--add-location=file includes file names only in comments, omitting line
numbers. If done again next time the files merge, then this will lessen the
diffs.
The results may include commented-out obsolete messages at the end, which
start with #~
At translator's discretion, these may be discarded when no longer helpful with
this command, substituting your filename twice for xx.po:
msgattrib -o xx.po --no-obsolete xx.po
101f6c7482