.\" Copyright (c) 1993 Michael Haardt (u31b3hs@pool.informatik.rwth-aachen.de), Fri Apr 2 11:32:09 MET DST 1993 .\" .\" This is free documentation; you can redistribute it and/or .\" modify it under the terms of the GNU General Public License as .\" published by the Free Software Foundation; either version 2 of .\" the License, or (at your option) any later version. .\" .\" The GNU General Public License's references to "object code" .\" and "executables" are to be interpreted as the output of any .\" document formatting or typesetting system, including .\" intermediate and printed output. .\" .\" This manual is distributed in the hope that it will be useful, .\" but WITHOUT ANY WARRANTY; without even the implied warranty of .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the .\" GNU General Public License for more details. .\" .\" You should have received a copy of the GNU General Public .\" License along with this manual; if not, write to the Free .\" Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, .\" USA. .\" .\" Modified Sun Jul 25 10:46:28 1993 by Rik Faith (faith@cs.unc.edu) .\" Modified Sun Aug 21 18:12:27 1994 by Rik Faith (faith@cs.unc.edu) .\" Modified Sun Jun 18 01:53:57 1995 by Andries Brouwer (aeb@cwi.nl) .TH PASSWD 5 "24 July 1993" "Linux" "Linux Programmer's Manual" .SH NAME passwd \- password file .SH DESCRIPTION .B Passwd is an ASCII file which contains a list of the system's users and the passwords they must use for access. The password file should have general read permission (many utilities, like .IR ls (1) use it to map user IDs to user names), but write access only for the superuser. .PP In the good old days there was no great problem with this general read permission. Everybody could read the encrypted passwords, but the hardware was too slow to crack a well-chosen password, and moreover, the basic assumption used to be that of a friendly user-community. These days many people run some version of the shadow password suite, where .I /etc/passwd has *'s instead of passwords, and the encrypted passwords are in .I /etc/shadow which is readable by root only. .PP When you create a new login, leave the password field empty and use \fBpasswd\fP(1) to fill it. A star (*) in the password field means that this user can not login via \fBlogin\fP(1). .PP There is one entry per line, and each line has the format: .sp .RS login_name:passwd:UID:GID:user_name:directory:shell .RE .sp The field descriptions are: .sp .RS .TP 1.0in .I login_name the name of the user on the system. .TP .I password the encrypted optional user password. .TP .I UID the numerical user ID. .TP .I GID the numerical group ID for this user. .TP .I user_name the (optional) comment field (often a full user name). .TP .I directory the user's $HOME directory. .TP .I shell the program to run at login (if empty, use .IR /bin/sh ). .RE .SH NOTE If your root file system is on .IR /dev/ram, you must save a changed password file to your root file system floppy before you shut down the system and check the access rights. If you want to create user groups, their GIDs must be equal and there must be an entry in \fI/etc/group\fP, or no group will exist. .SH FILES .I /etc/passwd .SH "SEE ALSO" .BR passwd (1), .BR login (1), .BR group (5), .BR shadow (5)