archlinux:downgrade

# 2013-03-17 刚才不小心更新了一下 curl
sudo pacman -S curl

# 结果 curl 跪了，所有的 pacman 命令也是
curl: /usr/lib/libc.so.6: version `GLIBC_2.17' not found (required by curl)
curl: /usr/lib/libc.so.6: version `GLIBC_2.17' not found (required by /usr/lib/libcurl.so.4)

# 于是很悲剧地连回滚 curl 都不行，幸好找到了不通过 pacman 命令回滚软件的方式
# https://bbs.archlinux.org/viewtopic.php?pid=1148260#p1148260
zcat /var/cache/pacman/pkg/curl-7.26.0-1-<arch>.pkg.tar.xz | tar xv -C /

# 如果 pacman 没跪
pacman -U /var/cache/pacman/pkg/<old-version-package>