This solution keeps the lines with most IPs first although not optimal it should give fairly more concise answers than just processing file top to bottom.
I tried it on a data files with 170K lines and it took approx 3 seconds to process.
All,
I have a text file with several entries like below:
personname
personname.domain.com
I know there is a way to use vi to remove only the personname.domain.com line. Can someone help? I believe that it involves /s/g/ something...I just can't remember the exact syntax.
Thanks (2 Replies)
Hi gurus,
i'm trying to remove a number of lines from a large file using the following command:
sed '1,5000d' oldfile > newfile
Somehow the lines in the old file are not deleted...
Am I doing this wrongly? Any suggestions? :confused:
Thanks! :)
wee (10 Replies)
A small question
I have a test.txt file
I have contents as:
a:google
b:yahoo
:
c:facebook
:
d:hotmail
How do I remove the line with :
my output should be
a:google
b:yahoo
c:facebook
d:hotmail (5 Replies)
Hi,
I'm not a expert in shell programming, so i've come here to take help from u gurus.
I'm trying to tailor a csv file that i got to make it work for the LOAD FROM command.
I've a datatable csv of the below format -
--in file format
xx,xx,xx ,xx , , , , ,,xx,
xxxx,, ,, xxx,... (11 Replies)
Hey Gang-
I have a list of servers. I want to exclude servers that begin with and end with certain characters. Is there an easy command to do this?
Example
wvm1234dev
wvm1234pro
uvm1122dev
uvm1122bku
uvm1344dev
I want to exclude any lines that start with "wvm" OR "uvm" AND end... (7 Replies)
Hi,
I have a huge file which has Lacs of lines. File system got full.
I want your guys help to suggest me a solution so that I can remove all lines from that file but not last 50,000 lines. I want solution which can remove lines from existing file so that I can have some space left with. (28 Replies)
I have a file that contains the following:
Party_Id1;Party_id2;Party_id3;
1;2;3;
0
0
4;5;6;
0
7;8;9;
How can I adjust the file so it looks like this:
Party_Id1;Party_id2;Party_id3;
1;2;3;
4;5;6;
7;8;9;
I Think the '0' is something like a carriage return, I don't know. But how... (2 Replies)
I have two files, a keepout.txt and a database.csv. They're unsorted, but could be sorted.
keepout:
user1
buser3
anuser19
notheruser27
database:
user1,2343,"information about",field,blah,34
user2,4231,"mo info",etc,stuff,43
notheruser27,4344,"hiya",thing,more thing,423... (4 Replies)
I have been searching and trying to come up with an awk that will perform the following on a
converted text file (original is a pdf).
1. Since the first two lines are (begin with) text they are removed
2. if $1 is a number then all text is merged (combined) into one line until the next... (3 Replies)
Discussion started by: cmccabe
3 Replies
LEARN ABOUT REDHAT
urandom
RANDOM(4) Linux Programmer's Manual RANDOM(4)NAME
random, urandom - kernel random number source devices
DESCRIPTION
The character special files /dev/random and /dev/urandom (present since Linux 1.3.30) provide an interface to the kernel's random number
generator. File /dev/random has major device number 1 and minor device number 8. File /dev/urandom has major device number 1 and minor
device number 9.
The random number generator gathers environmental noise from device drivers and other sources into an entropy pool. The generator also
keeps an estimate of the number of bit of the noise in the entropy pool. From this entropy pool random numbers are created.
When read, the /dev/random device will only return random bytes within the estimated number of bits of noise in the entropy pool.
/dev/random should be suitable for uses that need very high quality randomness such as one-time pad or key generation. When the entropy
pool is empty, reads to /dev/random will block until additional environmental noise is gathered.
When read, /dev/urandom device will return as many bytes as are requested. As a result, if there is not sufficient entropy in the entropy
pool, the returned values are theoretically vulnerable to a cryptographic attack on the algorithms used by the driver. Knowledge of how to
do this is not available in the current non-classified literature, but it is theoretically possible that such an attack may exist. If this
is a concern in your application, use /dev/random instead.
CONFIGURING
If your system does not have /dev/random and /dev/urandom created already, they can be created with the following commands:
mknod -m 644 /dev/random c 1 8
mknod -m 644 /dev/urandom c 1 9
chown root:root /dev/random /dev/urandom
When a Linux system starts up without much operator interaction, the entropy pool may be in a fairly predictable state. This reduces the
actual amount of noise in the entropy pool below the estimate. In order to counteract this effect, it helps to carry entropy pool informa-
tion across shut-downs and start-ups. To do this, add the following lines to an appropriate script which is run during the Linux system
start-up sequence:
echo "Initializing kernel random number generator..."
# Initialize kernel random number generator with random seed
# from last shut-down (or start-up) to this start-up. Load and
# then save 512 bytes, which is the size of the entropy pool.
if [ -f /var/random-seed ]; then
cat /var/random-seed >/dev/urandom
fi
dd if=/dev/urandom of=/var/random-seed count=1
Also, add the following lines in an appropriate script which is run during the Linux system shutdown:
# Carry a random seed from shut-down to start-up for the random
# number generator. Save 512 bytes, which is the size of the
# random number generator's entropy pool.
echo "Saving random seed..."
dd if=/dev/urandom of=/var/random-seed count=1
FILES
/dev/random
/dev/urandom
AUTHOR
The kernel's random number generator was written by Theodore Ts'o (tytso@athena.mit.edu).
SEE ALSO
mknod (1)
RFC 1750, "Randomness Recommendations for Security"
Linux 1997-08-01 RANDOM(4)