Passwd

From Wikipedia, the free encyclopedia

The correct title of this article is passwd. The initial letter is shown capitalized due to technical restrictions.

passwd is a tool on most Unix and Linux systems used to change a user's password. A key derivation function is used to encrypt the new password. Only the encrypted version is stored.

passwd generally works by manipulating the local username and password storage file (typically /etc/passwd, or /etc/shadow when shadow passwords are in use), which means that the changed password applies only for the computer on which the command was run. If PAM is in use, however, as it can be on Linux, Solaris, Mac OS X, and FreeBSD, then the passwd command can be used to change the password of whichever authentication mechanism is in use at the time, be that Sun's NIS, Kerberos, LDAP, or any other scheme for which there is a PAM module.

Prior to the advent of PAM, it was necessary to have different commands to change passwords in different authentication schemes. For example, the command to change a NIS password was yppasswd. This required users to be trained on different methods to change passwords for different systems, and also the wasteful duplication of code in the various programs that performed the same functions with different backends.

passwd can also be used as a noun, to refer generically to any password. It is most often used to refer to passwords on UNIX systems, as its etymology is owed to the command mentioned above.


Advanced Search
Included Web Search Engines


Safe Search

close

Top Matching Results

Occasionally Search.com will highlight specialized results that are based on the context of your query. Examples of specialized results include specific links to news, images, or video.

Top Matching Results may highlight information from other Search.com pages, content from the CNET Network of sites, or third party content. The listings are based purely on relevance. Search.com does not receive payment for listings in this section but our partners that provide this data may get paid for listing these products.

Sponsored Links

This section contains paid listings which have been purchased by companies that want to have their sites appear for specific search terms and related content. These listings are administered, sorted and maintained by a third party and are not endorsed by Search.com.

Search Results

Search.com sends your search query to several search engines at one time and integrates the results into one list which has been sorted by relevance using Search.com's proprietary algorithm. You can customize the list of search engines included in your metasearch from the preferences.

The search engines that are used in your metasearch may allow companies to pay to have their Web sites included within the results. To view the Paid Inclusion policy for a specific search engine, please visit their Web site. Search.com does not accept payment or share revenue with any search engine partner for listings in this section.