错误如下：
Setting up install-info (6.1.0.dfsg.1-5) ...
/usr/sbin/update-info-dir: 2: /etc/environment: source: not found
dpkg: error processing package install-info (--configure):
subprocess installed post-installation script returned error exit
status 127
Errors were encountered while processing:
install-info
E: Sub-process /usr/bin/dpkg returned an error code (1)
解决办法：
cd /var/lib/dpkg/info
sudo rm *.postinst
sudo apt-get update