The uco command is a perl program which you can use to reset your environment in case it has been corrupted or you have made a mistake in customising your environment. This command can be used to reset your shell profiles files, some of your mail default files and some of your security files. Type uco -h to get a quick help. In addition, this command can help you to set, reset or analyse some of your customisation. It can do it on several areas like the shell, X11, the setting of the keyboard in the context of X Window, the security, the structure of your home directory. It will present you a menu and you can choose what you want to do. You can set the flags -n to see what the command would do (without actually performing any operations). The -v flag is verbose mode and the command informs you what it is doing. . Of course it saves your files by appending a number in the file name. For example, assume that it is the first time you run uco on the shell area to reset your environment and lets assume that your login shell is tcsh, then you will find .tcshrc.1 and .login.1 files in your HOME directory. If it is the 1000th time you run the command you will find 1000 files in your HOME directory, the last ones being: .tcshrc.1000 and .login.1000