Red Hat ENTERPRISE LINUX 4 - STEP BY STEP GUIDE Manual

Also see for ENTERPRISE LINUX 4 - DEVELOPER TOOLS GUIDE: Installation guide Installation guide Tuning guide Installation guide Manual

Contents

126 Chapter 14. Frequently Asked Questions14.3. Forgotten user PasswordI’ve forgotten my user password. How do I get a new one?Passwords are stored in encrypted files on your Red Hat Enterprise Linux system: users cannot reada file and see their own or other passwords. If you forget your user password, you must create a newone.If you realize that you have forgotten your pasword while logged in, you can create a new one foryourself. Open a shell prompt and enter the command passwd. The passwd command asks for thenew password, which you will have to enter twice. The next time you log in, use the new password.If you are not logged in when you realize you have forgotten your password, log in as the root user.Open a shell prompt and enter the command passwd username, where username is your normaluser name. The passwd command requires you to enter the new password twice. Log out of yoursystem. You can now log back in with your normal user name and your new password.14.4. Changing PasswordsHow do I change my root or user password?The process for changing the password of root is the same as that for changing the password for auser. First, log in to the appropriate account. Open a shell prompt and enter the command passwd.The passwd command asks for the new password, which you will have to enter twice. The next timeyou log in, use the new password.14.5. Password MaintenanceHow often should I change my password? What should my password look like?For security reasons, it is a good idea to change your root and user passwords regularly. Experts varyon how often this change should occur, but most agree that passwords should be changed multipletimes each year.Passwords should not be based on a dictionary word should be at least six characters, and shouldinclude: both lower-case and upper-case letters, at least one number, and at least one punctuationmark. Don’t write your password down or store it in an unencrypted file. Don’t give your password toanyone.User passwords can be set to automatically expire after a certain amount of time. Refer to the Red HatEnterprise Linux System Administration Guide for more information.14.6. Starting ApplicationsI installed an application I downloaded from the Internet, and everything seemed to go fine, but I stillget command not found when I type its name. I think I have the right name, so why does it notstart?If you are trying to start an application from the shell prompt and it is not working, trytyping out the full directory path before the name of the application’s executable (such as/usr/local/bin/my-executable).For example, imagine that you have downloaded the setiathome client application and want to tryit out. You follow the directions for installing the software, which creates a subdirectory in your homedirectory called seti/. Now, start the application using the full path to the executable file as shownbelow:/home/joe/seti/setiathome