Can anyone tell me what the following line of code does?
This part :
uses the "sed" utility to search for a pattern in file "file1" and replace it by something, if it is found. If the pattern is not found, the line will be returned as it is.
This part:
redirects the output of the sed command above to another file called "file2". If it exists, the file "file2" will be overwritten, otherwise it will be created.
Now for the search/replace part:
Here's an example of the working of the sed command. I've omitted the redirection part at the end:
(a) Line 1 Both the numbers in the first line matched the pattern, hence they were replaced.
(b) Line 2 The first number in the second line did not match the pattern, because "2" was not followed by a number between "00" and "29" (both inclusive). It was followed by "34", so the first number was left as it is. The second number matched the pattern and was suitably replaced.
(c) Line 3 None of the two numbers matched the pattern, so the line was returned as it was.
hey gents,
I'm working on something that will use snmpwalk to query the devices on my network and retreive the device name, device IP, device model and device serial. I'm using Nmap for the enumeration and sed to clean up the results for use by snmpwalk. Once i get all the data organized I'm... (8 Replies)
I'm new to using sed and grep commands, but have found them extremely useful. However I am having a hard time figuring this one out:
Delete every line containing the word CEN and the next line as well.
ie. test.txt
blue
324 CEN
green
red
blue
324 CEN
green
red
blue
to produce:... (2 Replies)
I am trying to delete lines in archived Apache httpd logs
Each line has the pattern:
<ip-address> - - <date-time> <document-request-URL> <http-response> <size-of-req'd-doc> <referring-document-URL>
This pattern is shown in the example of 6 lines from the log in the code box below. These 6... (1 Reply)
my requirement is,
consider a file output
cat output
blah sdjfhjkd jsdfhjksdh
sdfs 23423 sdfsdf sdf"sdfsdf"sdfsdf"""""dsf
hellow there
this doesnt look good
et cetc etc
etcetera
i want to replace a line of line number 4 ("this doesnt look good") with some other line
... (3 Replies)
here is what i want to achieve.. i have a file with below contents
cat fileName
blah blah blah
.
.DROP this
REJECT that
.
--sport 7800 -j REJECT --reject-with icmp-port-unreachable
--dport 7800 -j REJECT --reject-with icmp-port-unreachable
.
.
.
more blah blah blah
--dport 3306... (14 Replies)
Hi,
I am running a script sample.sh in bash environment .In the script i am using sed and awk commands which when executed individually from terminal they are getting executed normally but when i give these sed and awk commands in the script it is giving the below errors :-
./sample.sh: line... (12 Replies)
Sed command to replace a line in a file using line number from the output of a pipe.
Is it possible to replace a whole line piped from someother command into a file at paritcular line...
here is some basic execution flow..
the line number is 412
lineNo=412
Now i have a line... (1 Reply)
Hi all,
Let's say I have a script calling for the two variables PA_VALUE and PB_VALUE.
for pa in PA_VALUE
blah blah
do
for pb in PB_VALUE
blah blah
do
I have a text file with two columns of values for PA and PB.
14.5 16.7
7.8 9.5
5.6 3.6
etc etc
I would like to read this... (7 Replies)
Hello,
I'm trying to figure out how to speed up the following as I want to use multiple commands to search thousands of files.
is there a way to speed things up?
Example I want to search a bunch of files for a specific line, if this line already exists do nothing, if it doesn't exist add it... (4 Replies)