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Full Discussion: Null Characters
Top Forums UNIX for Dummies Questions & Answers Null Characters Post 82221 by reborg on Monday 29th of August 2005 08:20:58 PM
Old 08-29-2005
What exactly do you mean, what are you using /dev/null for?

When I use it as a null device that exactly how it behaves:

Code:
user1@balrog ~
$ touch emptyfile

user1@balrog ~
$ ls -l emptyfile 
-rw-r--r--  1 user1 staff 0 Aug 30 01:15 emptyfile

user1@balrog ~
$ cp /dev/null emptyfile 

user1@balrog ~
$ ls -l emptyfile 
-rw-r--r--  1 user1 staff 0 Aug 30 01:15 emptyfile

user1@balrog ~
$ cat /dev/null > emptyfile 

user1@balrog ~
$ ls -l emptyfile 
-rw-r--r--  1 user1 staff 0 Aug 30 01:15 emptyfile

 

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LEARN ABOUT SUNOS

sulog

sulog(4)							   File Formats 							  sulog(4)

NAME

       sulog - su command log file

SYNOPSIS

       /var/adm/sulog

DESCRIPTION

       The  sulog file is a record of all attempts by users on the system  to execute the su(1M) command.  Each time  su(1M) is executed, an entry
       is added to the sulog file.

       Each entry in the sulog file is a single line of the form:

	      SU date time
	      result port user-newuser

       where

       date	       The month and date su(1M) was executed.	date is displayed in the form  mm/dd where  mm is the month number and dd  is  the
		       day number in the month.

       time	       The  time   su(1M) was executed. time is displayed in the form  HH/MM where  HH is the hour number (24 hour system) and	MM
		       is the minute number.

       result	       The result of the  su(1M) command.  A ` + ' sign is displayed in this field if the su attempt was successful; otherwise	 a
		       ` - ' sign is displayed.

       port	       The name of the terminal device from which  su(1M) was executed.

       user	       The user id of the user executing the  su(1M) command.

       newuser	       The user id being switched to with  su(1M).

EXAMPLES

       Example 1: A sample sulog file.

       Here is a sample sulog file:

       SU 02/25 09:29 + console root-sys
       SU 02/25 09:32 + pts/3 user1-root
       SU 03/02 08:03 + pts/5 user1-root
       SU 03/03 08:19 + pts/5 user1-root
       SU 03/09 14:24 - pts/5 guest3-root
       SU 03/09 14:24 - pts/5 guest3-root
       SU 03/14 08:31 + pts/4 user1-root

FILES

       /var/adm/sulog	       su log file

       /etc/default/su	       contains the default location of  sulog

SEE ALSO

       su(1M)

SunOS 5.10							    6 Jun 1994								  sulog(4)
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