COHERENT manpages
This page displays the COHERENT manpage for passwd [Define system users].
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passwd -- System Administration Define system users The file /etc/passwd holds information about each user who has permission to use the COHERENT system. This information is read by the commands login and passwd whenever a user attempts to log in, to ensure that that user is really himself and not an impostor. /etc/passwd holds one record for each user; each record, in turn, consists of seven colon-separated fields, as follows: name:password:user_id:group_id:comments:home_dir:shell name is the user's login name. password is his encrypted password. If this field holds a single asterisk `*', then the program login reads his password out of the file /etc/shadow. user_id is a unique number that is also used to identify the user. group_id identifies the group to which the user belongs, if any. comments holds miscellaneous data, such as names, telephone numbers, or office numbers. home_dir gives the user's home directory. Finally, shell gives the program that is first executed when the user logs on; in most instances, this is an interactive shell (default, /bin/sh). If you wish, you can set additional passwords to control users who attempt to log into your system remotely (that is, via a modem). You can set a different remote-access password for each group of users, based on the program invoked when they log in; for example, you can set one password for the users who log in and invoke uucico, and another for the users who log in and invoke the interactive shells ksh or sh. For details on how to do this, see the Lexicon entries d_passwd and dialups. When a user creates a file, that file is ``owned'' by him. For example, whenever user joe create a file, that file is ``owned'' by joe; and joe has user-level permissions on that file. The superuser root can use the command chown to change the ownership of a file from one user to another. For details on this command, see its entry in the Lexicon. See Also Administering COHERENT, chown, passwd [command] Notes /etc/passwd can be read by anyone: if access to it were refused to a user, he could not log on. Thus, the passwords encrypted within it can be read and copied by anyone, and so may be vulnerable to brute-force decryption. For this reason, close attention should be paid to passwords: they should not be common words or names, preferably mix cases or use unique spellings, and be at least six characters long.