Managing many accounts

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passwd does not echo the characters typed at the prompt. This would pro 

vide several ways to  steal  your password, including just looking over your

shoulder as you enter it.

Once passwd verifies that the password is correct, the new password is re 

quested. When it has been entered the new password will be requested again.

If you can type the same password twice, it is assumed that you can type it

again whenever you need to. This will fail if the two passwords don't match.

This keeps the stray character from becoming part of the password. Some 

times when you press the key you wish to press you also press another by

mistake. Since these keys are not echoed to the screen, you get no feedback

that this has occurred. By asking for the password twice, these mistakes are

filtered out. As a result, you may sometimes be asked to try again, even when

you thought you got it right. No matter how clumsy you may be, passwd will

let you keep trying until you get it right.

Once Fred types his new secret password twice correctly, passwd makes the

entries that make that password the new one for this account. The password

will not change unless Fred, or someone with root privilege, changes it. This

makes the security of root privileges very important on a system with many

users just like Fred. Each of these users expect their files to be secure and

unaltered by another user account, relying on those with root privileges to not

abuse those privileges. This trust between the system administrator (usually

the only one with root access to the system) and the users is a relationship

in which some are very good and some can be overbearing. However, the best

administrator can have a password stolen or otherwise compromised. The

person who would do this may not worry about the other people's files, making

all precautions useless.