Twin directories of m4:

[DIR]  ftp://ftp.dit.upm.es/linux/ubuntu-6.06.1/ubuntu-6.06.1/pool/main/m/m4/
[DIR]  ftp://ftp.eenet.ee/arhiiv/gnu/gnu/Manuals/automake-1.4/m4/
[DIR]  ftp://ftp.linux.it/ubuntu/pool/main/m/m4/
[DIR]  ftp://ftp.linux.it/debian/pool/main/m/m4/
[DIR]  ftp://134.121.1.1/.snapshot/nightly.3/pub/gnu/m4/
[DIR]  ftp://134.121.1.1/pub/gnu.OLD/m4/
[DIR]  ftp://134.121.1.1/.snapshot/nightly.2/pub/gnu/m4/
[DIR]  ftp://134.121.1.1/.snapshot/nightly.3/pub/gnu/Manuals/automake-1.4/m4/
[DIR]  ftp://134.121.1.1/.snapshot/nightly.1/pub/gnu/m4/
[DIR]  ftp://134.121.1.1/.snapshot/nightly.0/pub/gnu/m4/
[DIR]  ftp://134.121.1.1/.snapshot/hourly.1/pub/gnu/m4/
[DIR]  ftp://134.121.1.1/pub/gnu.OLD/Manuals/automake-1.4/m4/
[DIR]  ftp://ftp.eutelia.it/pub/Slackware_Mirror/slackware-12.1/source/d/m4/
[DIR]  ftp://ftp.eutelia.it/pub/Slackware_Mirror/slackware-current/source/d/m4/
[DIR]  ftp://ftp.eutelia.it/pub/Slackware_Mirror/slackware-11.0/patches/source/m4/
[DIR]  ftp://ftp.eutelia.it/pub/Slackware_Mirror/slackware-11.0/source/d/m4/
[DIR]  ftp://ftp.eutelia.it/pub/Slackware_Mirror/slackware-12.0/patches/source/m4/
[DIR]  ftp://ftp.eutelia.it/pub/Slackware_Mirror/slackware-12.0/source/d/m4/
[DIR]  ftp://ftp.cesca.es/mirror2/gnu/Manuals/m4/
[DIR]  ftp://ftp.cesca.es/mirror2/gnu/m4/
[DIR]  ftp://ftp.cesca.es/mirror2/gnu/Manuals/automake-1.4/m4/
[DIR]  ftp://ftp.cesca.es/mirror/debian/pool/main/m/m4/
[DIR]  ftp://ftp.saintjoe.edu/pub/linux/slackware/slackware-current/source/d/m4/
[DIR]  ftp://ftp.uni-frankfurt.de/pub/Mirrors3/debian.org/debian/pool/main/m/m4/
[DIR]  ftp://ftp.inf.utfsm.cl/pub/tex-archive/support/chktex/m4/
[DIR]  ftp://ftp.inf.utfsm.cl/pub/tex-archive/macros/texinfo/contrib/texinfo-hu/texinfo/m4/
[DIR]  ftp://ftp.inf.utfsm.cl/pub/tex-archive/macros/texinfo/texinfo/gnulib/m4/
[DIR]  ftp://ftp.inf.utfsm.cl/pub/gnu/m4/
[DIR]  ftp://ftp.uni-magdeburg.de/pub/mirror/linux/slackware/source/d/m4/
[DIR]  ftp://ftp.uni-magdeburg.de/pub/mirror/linux/debian/pool/main/m/m4/
[DIR]  ftp://ftp.hpl.hp.com/gatekeeper/pub/cygwin/release/m4/
[DIR]  ftp://aeneas.mit.edu/pub/gnu/m4/
[DIR]  ftp://aeneas.mit.edu/pub/gnu/Manuals/automake-1.4/m4/
[DIR]  ftp://ftp.afps.chel.su/pub/UNIX/m4/
[DIR]  ftp://debian.lcs.mit.edu/pub/debian-amd64/debian-amd64/pool/main/m/m4/
[DIR]  ftp://debian.lcs.mit.edu/pub/debian-amd64/debian/pool/main/m/m4/
[DIR]  ftp://debian.lcs.mit.edu/debian/pool/main/m/m4/
[DIR]  ftp://ftp.kfki.hu/pub/linux/ubuntu/pool/main/m/m4/
[DIR]  ftp://ftp.kfki.hu/pub/linux/debian/pool/main/m/m4/
[DIR]  ftp://ftp.internat.freebsd.org/pub/mesh/pc/MIT/click/etc/samplepackage/m4/
[DIR]  ftp://ftp.internat.freebsd.org/pub/mesh/pc/MIT/click/m4/
[DIR]  ftp://ftp.internat.freebsd.org/pub/FreeBSD/ports/devel/m4/
[DIR]  ftp://ftp.psi.ch/PSI_outgoing/salathe/Kappa/Kappa/front/m4/
[DIR]  ftp://ftp.psi.ch/PSI_outgoing/salathe/Kappa/Kappa/phi/huber_1_better/m4/
[DIR]  ftp://ftp.psi.ch/PSI_outgoing/salathe/Kappa/front/m4/
[DIR]  ftp://ftp.psi.ch/PSI_outgoing/salathe/Kappa/phi/huber_1_better/m4/
[DIR]  ftp://ftp.psi.ch/PSI_outgoing/salathe/marco/marco_flexor_test/flexor_SP_small/m4/
[DIR]  ftp://ftp.cprm.net/.disk0/slackware/slackware-12.1/source/d/m4/
[DIR]  ftp://ftp.armedslack.org/armedslack/armedslack-11.0/source/d/m4/
[DIR]  ftp://ftp.armedslack.org/armedslack/armedslack-current/source/d/m4/