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Linux in a Nutshell

This directory of Linux commands is from Linux in a Nutshell, 5th Edition.

Click on any of the 687 commands below to get a description and list of available options. All links in the command summaries point to the online version of the book on Safari Bookshelf.

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pwconv pwunconv

System administration command. Convert unshadowed entries in /etc/passwd into shadowed entries in /etc/shadow. Replace the encrypted password in /etc/password with an x. Shadowing passwords keeps them safe from password-cracking programs. pwconv creates additional expiration information for the /etc/shadow file from entries in your /etc/login.defs file. If you add new entries to the /etc/passwd file, you can run pwconv again to transfer the new information to /etc/shadow. Already shadowed entries are ignored. pwunconv restores the encrypted passwords to your /etc/passwd file and removes the /etc/shadow file. Some expiration information is lost in the conversion. See also grpconv and grpunconv.

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