LDP
/
man-pages
mirror of https://github.com/mkerrisk/man-pages
0
1
Fork 0
Code Releases Activity

passwd.5: Various minor rewordings 

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This commit is contained in:
Michael Kerrisk 2010-10-21 11:05:40 +02:00
parent 91567885b5
commit df0c9b98a7
1 changed files with 19 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

40
man5/passwd.5
View File

@ -26,16 +26,14 @@
.\" Modified Sun Jun 18 01:53:57 1995 by Andries Brouwer (aeb@cwi.nl)
.\" Modified Mon Jan 5 20:24:40 MET 1998 by Michael Haardt
.\" (michael@cantor.informatik.rwth-aachen.de)
.TH PASSWD 5 1998-01-05 "Linux" "Linux Programmer's Manual"
.TH PASSWD 5 2010-10-21 "Linux" "Linux Programmer's Manual"
.SH NAME
passwd \- password file
.SH DESCRIPTION
.B Passwd
is a text file, that contains a list of the system's accounts,
giving for each account some useful information like user ID,
group ID, home directory, shell, etc.
Often, it also contains the encrypted passwords for each account.
It should have general read permission (many utilities, like
The
.IR /etc/passwd
file is a text file that describes user login accounts for the system.
It should have read permission allowed for all users (many utilities, like
.BR ls (1)
use it to map user IDs to usernames), but write access only for the
superuser.
@ -43,33 +41,33 @@ superuser.
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
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 asterisks (*) instead of encrypted passwords,
and the encrypted passwords are in
.I /etc/shadow
.IR /etc/shadow ,
which is readable by the superuser only.
.PP
Regardless of whether shadow passwords are used, many sysadmins
Regardless of whether shadow passwords are used, many system administrators
use an asterisk in the encrypted password field to make sure
that this user can not authenticate him- or herself using a
password.
(But see the Notes below.)
(But see NOTES below.)
.PP
If you create a new login, first put an asterisk in the password field,
then use
.BR passwd (1)
to set it.
.PP
There is one entry per line, and each line has the format:
Each line of the file describes a single user, and has the following format:
.sp
.RS
account:password:UID:GID:GECOS:directory:shell
.RE
.sp
The field descriptions are:
The field are as follows:
.TP 12
.I account
the name of the user on the system.
@ -82,16 +80,16 @@ the encrypted user password, an asterisk (*), or the letter \(aqx\(aq.
for an explanation of \(aqx\(aq.)
.TP
.I UID
the numerical user ID.
the numeric user ID.
.TP
.I GID
the numerical primary group ID for this user.
the numeric primary group ID for this user.
.TP
.I GECOS
This field is optional and only used for informational purposes.
This field is optional and used only for informational purposes.
Usually, it contains the full username.
GECOS means General Electric
Comprehensive Operating System, which has been renamed to GCOS when
GECOS stands for "General Electric Comprehensive Operating System",
which was renamed to GCOS when
GE's large systems division was sold to Honeywell.
Dennis Ritchie has reported: "Sometimes we sent printer output or
batch jobs to the GCOS machine.
@ -113,9 +111,9 @@ through
.SH FILES
.I /etc/passwd
.SH NOTES
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.
If you want to create user groups, there must be an entry in
.IR /etc/group ,
or no group will exist.
.PP
If the encrypted password is set to an asterisk, the user will be unable
to login using