The example command in the GNU mailutils documentation
(http://mailutils.org/manual/html_node/mailutils-2047.html) fails, printing
"mailutils: don't know what 2047 is" as the error message. Running it with
strace shows the root cause:
stat("/usr/lib/mailutils/mailutils/mailutils-2047", 0x7ffd569d7770) = -1 ENOENT
(No such file or directory)
The build process for mailutils-3.4 actually produces an executable file
mu/libexec/.libs/mailutils-flt2047, but it is never packaged into any .deb. If
you build mailutils-3.4 using dpkg-buildpackage, then manually install that
binary:
# mkdir -p /usr/lib/mailutils/mailutils
# cp ./mu/libexec/.libs/mailutils-flt2047 /usr/lib/mailutils/mailutils/
… then you would be able to run `mailutils flt2047`. (Note that the command is
named "flt2047", in contrast to the documentation, which calls it "2047".
That's an upstream bug.)