Compared with Bash 4.2, the development version of bash is very slow in running autoconf-generated configure scripts (or, to be more precise, that's where I noticed the slowness; it might very well be more generalized, but I haven't checked for that).
Some numbers: $ /bin/bash -c 'echo "$BASH_VERSION"' 4.2.45(1)-release $ time CONFIG_SHELL=/bin/bash /bin/bash \ > ./configure CONFIG_SHELL=/bin/bash ... real 1m10.935s user 0m29.738s sys 0m12.669s $ $HOME/bleeding/bin/bash -c 'echo "$BASH_VERSION"' 4.3.0(1)-alpha $ time CONFIG_SHELL=$HOME/bleeding/bin/bash $HOME/bleeding/bin/bash \ > ./configure CONFIG_SHELL=$HOME/bleeding/bin/bash ... real 4m45.671s user 4m22.744s sys 0m17.753s Four times slower, yikes. Any idea where these numbers might be coming from? Regards, Stefano