NULL(4) Kernel Interfaces Manual NULL(4)NAME
null - data sink
SYNOPSIS
major device number(s):
raw: 1
minor device encoding:
mem: 0; kmem: 1; null: 2
DESCRIPTION
Data written on a null special file is discarded.
Reads from a null special file always return 0 bytes.
FILES
/dev/null
/dev/MAKEDEV script to create special files
/dev/MAKEDEV.local script to localize special files
SEE ALSO mem(4)3rd Berkeley Distribution January 28, 1988 NULL(4)
Check Out this Related Man Page
MEM(4) Kernel Interfaces Manual MEM(4)NAME
mem, kmem - main memory
SYNOPSIS
major device number(s):
raw: 1
minor device encoding:
mem: 0; kmem: 1; null: 2
DESCRIPTION
Mem is a special file that is an image of the main memory of the computer. It may be used, for example, to examine (and even to patch) the
system.
Byte addresses in mem are interpreted as physical memory addresses. References to non-existent locations cause errors to be returned.
The file kmem is the same as mem except that kernel virtual memory rather than physical memory is accessed. Only kernel virtual addresses
that are mapped to memory are allowed. Examining and patching device registers is likely to lead to unexpected results when read-only or
write-only bits are present.
On PDP-11s, the I/O page begins at location 0160000 of kmem and the per-process data segment for the current process begins at 0140000 and
is USIZE clicks (64 bytes each) long.
FILES
/dev/mem
/dev/kmem
/dev/MAKEDEV script to create special files
/dev/MAKEDEV.local script to localize special files
BUGS
On PDP-11's, specifying an odd kernel or user address, or an odd transfer count is [generally] slower than using all even parameters.
On machines with ENABLE/34(tm) memory mapping boards the I/O page can be accessed only through kmem.
3rd Berkeley Distribution January 28, 1988 MEM(4)
Hi,
I would like to know which files contain a certain string. If I use 'grep "string" *' only the working directory is being searched. I also want to search the subdirectories. When I use 'find . -type f -print |xargs grep "string" > dev/null' I get the message 'xargs: missing quote?'. What's... (11 Replies)
im having trouble with moving files in a directory into /dev/null
for file in $HOME/.trashcan/
do
mv $file /dev/null
done
the error msg i get is:
mv: /dev/null: not a directory.
does anyone know how to fix this?
thanks
primal (16 Replies)
Hi, Anyone can help
My solaris 8 system has the following
/dev/null , /dev/tty and /dev/console
All permission are lrwxrwxrwx
Can this be change to a non-world write ??
any impact ?? (12 Replies)
hi all,
iam new to this forum.i have to submit the script EOD.so please help me.
my requirement is to compare two null values..iam trying to compare two null values :One null value output of the storedprocedure and another iam giving spaces in script.
it is giving the error... (11 Replies)
We have a code to find the DNS entry of a host that has a trailing '-' in its url (format example: mysite-.watch.com):
if(gethostbyname_r(host,host_ent,host_buffer,host_buffer_size,&host_error)==NULL)
{
//failed
}
But when remove the '-' from the host name the code does not return... (12 Replies)
Hi All,
I have a file with 10 columns and get the required data for nine columns properly except 8th. In 8th column i have both NULL and NON NULL values...i.e
certain records have values for all the columns including 8th column and certain records have 8th column as NULL.My requisite is,without... (20 Replies)
hi,
i have to put in my script a command that should tell me if the contents of two different paths are the same.
I thought to write an "if" command who makes the diff of two files which contains the `ls` of the folders and go on with the script if is not null, but i'm afraid of the fact... (13 Replies)
Hi,
after a server (solaris 10) got rebooted, Im faced with the problem that in one of my zones (whole zone) /dev/null is only writeable for root
crw-r--r-- 1 root sys 13, 2 Jul 8 10:16 /dev/null
Unfortunatly chmod didnt help at this point and since its a productive system I dont... (11 Replies)
Hi all,
I want to compute for the average of a file with null values (NaN) for each row. any help on how to do it. the sample file looks like this.
1.4 1.2 1.5 NaN 1.6
1.3 1.1 NaN 1.3 NaN
2.4 1.3 1.5 NaN 1.5
NaN 1.2 NaN 1.4 NaN
I need to do a row-wise averaging such that it will sum only... (14 Replies)
Hi,
I have a log file which is having some xml tags. I need to check the value for a particular xml field is null or not and if it is null i have to add current time as the value for that xml field.
I tried below code to check whether the word count is 0. But even if the xml field is null it... (16 Replies)
Hi,
I've a pipe delimited file and wanted to replace the 3rd field to 099990 where the values are null. How can I achieve it using awk or sed.
20130516|00000061|02210|111554|03710|2|205069|SM APPL $80-100 RTL|S
20130516|00000061|02210|111554|03710|2|205069|SM APPL $80-100 RTL|S... (12 Replies)
I am working on a file with several columns as below
MO_NAME,FAULT_TYPE,CLASS,CODE1,CODE2,CODE3
RXOCF-101,BTS INTERNAL,FAULT CODES CLASS 2A,53,58
RXOCF-101,BTS INTERNAL,FAULT CODES CLASS 2B,24
RXOCF-101,BTS INTERNAL,FAULT CODES CLASS 2A,33
RXOCF-101,BTS INTERNAL,FAULT CODES CLASS 2D,57 ... (12 Replies)
Hi All
My requirement is to find the null values in particular column of a file and reject it in case if it contains null values. But the challenge is that I want a common command which can be used across different file, as the position of the column we need to check for different file may get... (14 Replies)