I have sys-devel/autoconf-2.57-r1 installed. It's only version of autoconf in my system. However when I run command autoconf --version I get: Autoconf version 2.13 I noticed this when Rosegarden's installation program checked my system and complained I have too old autoconf. And it's really brand new... Reproducible: Always Steps to Reproduce: 1. Run autoconf --version 2. 3. Actual Results: I get: Autoconf version 2.13 Expected Results: Return version 2.57 Portage 2.0.49-r15 (default-x86-1.4, gcc-3.2.3, glibc-2.3.2-r1, 2.6.0-test6) ================================================================= System uname: 2.6.0-test6 i686 AMD Duron(tm) processor Gentoo Base System version 1.4.3.10p1 ACCEPT_KEYWORDS="x86" AUTOCLEAN="yes" CFLAGS="-O2 -mcpu=i686 -pipe" CHOST="i686-pc-linux-gnu" COMPILER="gcc3" CONFIG_PROTECT="/etc /var/qmail/control /usr/kde/2/share/config /usr/kde/3/share/config /usr/X11R6/lib/X11/xkb /usr/kde/3.1/share/config /usr/share/texmf/tex/generic/config/ /usr/share/texmf/tex/platex/config/ /usr/share/config" CONFIG_PROTECT_MASK="/etc/gconf /etc/env.d" CXXFLAGS="-O2 -mcpu=i686 -pipe" DISTDIR="/usr/portage/distfiles" FEATURES="sandbox ccache autoaddcvs" GENTOO_MIRRORS="http://gentoo.oregonstate.edu http://distro.ibiblio.org/pub/Linux/distributions/gentoo" MAKEOPTS="-j2" PKGDIR="/usr/portage/packages" PORTAGE_TMPDIR="/var/tmp" PORTDIR="/usr/portage" PORTDIR_OVERLAY="" SYNC="rsync://rsync.gentoo.org/gentoo-portage" USE="x86 oss apm avi crypt encode foomaticdb gif jpeg libg++ mad mikmod mpeg ncurses nls pdflib png quicktime spell xml2 xmms xv zlib alsa gdbm berkdb slang readline arts tetex svga java X sdl gpm tcpd pam libwww ssl perl python esd imlib oggvorbis motif opengl mozilla qt kde cups tcltk gnome gtk truetype"
autoconf's ebuild installs several versions of autoconf. The versions are switched with the /usr/bin/autoconf perl script, which then calls the requested version of autoconf. From the script's comments: # Executes the correct autoconf version. # # - defaults to autoconf-2.13 # - runs autoconf-2.57a if it exists and... # - envvar WANT_AUTOCONF_2_5 is set to `1' # -or-