如何在安装新软件时删除错误消息
首先我通过终端安装了oracle java。 它得到了错误。 我不记得错误信息。 但其他java应用程序正在运行示例netbeans，eclipse。 主要问题是当我通过终端或ubuntu软件中心安装任何新软件时，首先我得到这个错误。
sha256sum mismatch jdk-7u3-linux-i586.tar.gz Oracle JDK 7 is NOT installed. dpkg: error processing oracle-java7-installer (--configure): subprocess installed post-installation script returned error exit status 1 Errors were encountered while processing: oracle-java7-installer E: Sub-process /usr/bin/dpkg returned an error code (1) 如何删除此消息并正确地重新安装java。 我正在使用Ubuntu 12.04
编辑当我试图删除Sun Java（TM）开发工具包（JDK）7时，我收到此错误消息。
installArchives() failed: (Reading database ... (Reading database ... 5% (Reading database ... 10% (Reading database ... 15% (Reading database ... 20% (Reading database ... 25% (Reading database ... 30% (Reading database ... 35% (Reading database ... 40% (Reading database ... 45% (Reading database ... 50% (Reading database ... 55% (Reading database ... 60% (Reading database ... 65% (Reading database ... 70% (Reading database ... 75% (Reading database ... 80% (Reading database ... 85% (Reading database ... 90% (Reading database ... 95% (Reading database ... 100% (Reading database ... 189962 files and directories currently installed.) Removing oracle-java7-installer ... update-alternatives: error: unknown argument `cdrom' dpkg: error processing oracle-java7-installer (--remove): subprocess installed pre-removal script returned error exit status 2 No apport report written because MaxReports is reached already Downloading... --2012-05-21 22:54:41-- http://download.oracle.com/otn-pub/java/jdk/7u3-b04/jdk-7u3-linux-i586.tar.gz Resolving download.oracle.com (download.oracle.com)... 222.165.168.249, 222.165.168.202 Connecting to download.oracle.com (download.oracle.com)|222.165.168.249|:80... connected. HTTP request sent, awaiting response... 302 Moved Temporarily Location: https://edelivery.oracle.com/otn-pub/java/jdk/7u3-b04/jdk-7u3-linux-i586.tar.gz [following] --2012-05-21 22:54:42-- https://edelivery.oracle.com/otn-pub/java/jdk/7u3-b04/jdk-7u3-linux-i586.tar.gz Resolving edelivery.oracle.com (edelivery.oracle.com)... 173.222.122.174 Connecting to edelivery.oracle.com (edelivery.oracle.com)|173.222.122.174|:443... connected. HTTP request sent, awaiting response... 302 Moved Temporarily Location: http://download.oracle.com/errors/download-fail-1505220.html [following] --2012-05-21 22:54:43-- http://download.oracle.com/errors/download-fail-1505220.html Connecting to download.oracle.com (download.oracle.com)|222.165.168.249|:80... connected. HTTP request sent, awaiting response... 200 OK Length: 5307 (5.2K) [text/html] Saving to: `./jdk-7u3-linux-i586.tar.gz' 0K ..... 100% 152K=0.03s 2012-05-21 22:54:43 (152 KB/s) - `./jdk-7u3-linux-i586.tar.gz' saved [5307/5307] Download done. sha256sum mismatch jdk-7u3-linux-i586.tar.gz Oracle JDK 7 is NOT installed. dpkg: error while cleaning up: subprocess installed post-installation script returned error exit status 1 Errors were encountered while processing: oracle-java7-installer
运行这些命令应解决您的问题：
sudo apt-get update sudo apt-get --purge reinstall oracle-java7-installer sudo apt-get upgrade
如果他们不这样做，那么请编辑你的问题，以包括终端运行时的所有文本（因为输出仍然在诊断上有用）。
实际上，修复非常简单。 请先在Ubuntu软件中心安装Synaptic Package Manager。 安装后，您需要使用root权限打开它：
sudo synaptic
搜索Oracle-java7-installer，右键单击它，然后将其完全删除。 应用更改，删除PPA，您的错误消息将消失。 
Synaptic Package Manager在删除具有依赖性问题的文件时非常有用，特别是当sudo apt-get install -f不起作用时。