'!!' in /etc/shadow


 
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# 1  
Old 12-03-2010
'!!' in /etc/shadow

I notice there are '*'s and '!!'s in my /etc/shadow file.
And I know these are for preventing login. But what are the differences among '*', '!' and '!!' ?
THX!
Code:
mail:*:14789:0:99999:7:::
uucp:*:14789:0:99999:7:::
...
dbus:!!:14919::::::
rpc:!!:14919:0:99999:7:::
...
jone:!!:14946:0:99999:7:::

PS:"jone" is a user added by useradd command.
# 2  
Old 12-03-2010
man 5 shadow suggests * and !! in the shadow file should have the same effect -- any character that crypt(3) wouldn't accept means that user is unable to log in with a password. I surmise you haven't set jones' password yet.
# 3  
Old 12-03-2010
"!!" means the password has/is expired...
# 4  
Old 12-04-2010
I haven't set jone's password.

But what if a single exclamation like this '!' ? or double star like this '**' ?
# 5  
Old 12-04-2010
Metacharacters

Metacharacter
Description


Quote:
Wikipedia says

UNIX interprets a space as a separator not as a character.
*
A wild card character that matches any group of characters of any length, allowing a user to specify a large group of items with a short string. For example, to specify all the files that start with 'abc', you use abc*.
?
A wild card character that matches any single character. Thus ls ??? lists files in the current directory whose names are only three characters long, while ls ???.* lists those files with a three letter main name and any extension.
[..]
A set of characters that can be matched. Thus ls [a-c]*.??? lists all files that begin with a, b, or c and have a three letter extension and lpr [ad]* prints all files that begin with a or d.
$
Indicates that the following text is the name of a shell (environment) variable whose value is to be used.
|
Separates commands to form a pipe (see redirection in "Intermediate Use Of The UNIX Operating System").
<
Redirect the standard input (see redirection in "Intermediate Use Of The UNIX Operating System").
>
Redirect the standard output (see redirection in "Intermediate Use Of The UNIX Operating System") to replace current contents.
>>
Redirect the standard output (see redirection in "Intermediate Use Of The UNIX Operating System") to append to current contents.
>&
Redirect the standard output and standard error (see redirection in "Intermediate Use Of The UNIX Operating System") to replace current contents.
>>&
Redirect the standard output an standard error (see redirection in "Intermediate Use Of The UNIX Operating System") to append to current contents.
%
Introduces a job name (see multitasking in "Intermediate Use Of The UNIX Operating System").
&
Place a process into the background (see multitasking in "Intermediate Use Of The UNIX Operating System").
()
Encloses a sequence of commands or pipes to be executed as a single command.
!
Precedes a history substitution (see "man history")
;
Separates sequences of commands (or pipes) that are on one line.
&&
Separates two sequences of commands or pipes the second of which is executed only if the first succeeds.
||
Separates two sequences of commands or pipes the second of which is executed only if the first fails.
\
Used to "quote" the following metacharacter so it is treated as a plain character, as in \*.
 
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