Need command or script to fetch only specific paragraph from a file in Unix/Linux
Files formatting is like
=================================
THREAD NUMBER
MESSAGE NUMBER
Severity
File_LOCATION
FUNCTION_NAME
LINE_NUMBER
TIME STAMP
BLANK LINE
SINGLE LINE ERROR TEXT
=================================
Here i Want to extract only severity and message text part for user input severity.
Try this:
awk "/Severity: $1/,/File_LOCATION/" < file_name > out.txt
Maybe you can use cat file | tail --lines=+3 | head -1 to get the third line out of the given file. But I don't know if this is what you want or need.
Related
This question already has answers here:
Unix command to prepend text to a file
(21 answers)
Closed 2 years ago.
Real nit picky Linux question.
I have a text file, call it userec. I also have a string variable 'var_a'.
I want to concatenate the string value, let just say it's 'howdy' to the top of the text file.
So something like
echo $var_a | cat usrec > file_out
where it pipes the output from the echo $var_a as a file and adds it to the top of file_out and then adds the rest of the usrec file.
So if the userec file contains just the line 'This is the second line' then the contents of file_out should be:
howdy
This is the second line.
problem is that's not what the command is doing and I do not want to create a variable to store var_a in. This is running from a script and I don't want to create any extra flack to have to clean up afterwards.
I've tried other variations and I'm comming up empty.
Can anyone help me?
If you give cat any file names then it does not automatically read its standard input. In that case, you must use the special argument - in the file list to tell it to read the standard input, and where to include it in the concatenated output. Since apparently you want it to go at the beginning, that would be:
echo $var_a | cat - usrec > file_out
I would simply do :
echo $var_a > file_out
cat usrec >> file_out
I am new to Shellscripting.I am working on a poc in which a script should read a log file and then append to a existing file for the purpose of alert.It should work as per below
There will be some predefined format according to which it will decide whether to append in file or not.For example:
WWXXX9999XS message
**XXX** - is a 3 letter acronym (application code) like for **tom** for tomcat application
9999 - is a 4 numeric digit in the range 1001-1999
**E or X** - For notification X ,If open/active alerts already existing for same error code and same message,new alerts will not be raised for existing one.Once you have closed existing alerts,it will raise alarm for new error.There is any change in message for same error code from existing one, it will raise a alarm even though open/active alerts present.
X option is only for drop duplicates on code and message otherwise all alert mechanisms are same.
**S** - is the severity level, I.e 2,3
**message** - is any text that will be displayed
The script will examine the log file, and look for error like cloud server is down,then it would append 'wwclo1002X2 cloud server is down'if its a new alert.
2.If the same alert is coming again,then it should append 'wwclo1002E2 cloud server is down
There are some very handy commands you can use to do this type of File manipulation. I've updated this in response to your comment to allow functionality that will check if the error has already been appended to the new file.
My suggestion would be that there is enough functionality here to warrant saving it in a bash script.
My approach would be to use a combination of less, grep and > to read and parse the file and then append to the new file. First save the following into a bash script (e.g. a file named script.sh)
#!/bin/bash
result=$(less $1 | grep $2)
exists=$(less $3 | grep $2)
if [[ "$exists" == "$result" ]]; then
echo "error, already present in file"
exit 1
else
echo $result >> $3
exit 0
fi
Then use this file in the command passing in the log file as the first argument, the string to search for as the second argument and the target results file as the third argument like this:
./script.sh <logFileName> "errorToSearchFor" <resultsTargetFileName>
Don't forget to run the file you will need to change the permissions - you can do this using:
chmod u+x script.sh
Just to clarify as you have mentioned you are new to scripting - the less command will output the entire file, the | command (an unnamed pipe) will pass this output to the grep command which will then search the file for the expression in quotes and return all lines from the file containing that expression. The output of the grep command is then appended to the new file with >>.
You may need to tailor the expression in quotes after grep to get exactly the output you want from the log file.
The filenames are just placeholders, be sure to update these with the correct file names. Hope this helps!
Note updated > to >> (single angle bracket overwrites, double angle bracket appends
this is my first question here so please bear with me.
I have a large text file from which I need only one specific part of one line. I can grep the line but I do not know how I can get that specific part out of that line.
here is my text line (stored in output.txt)
><source src="https://download.foobar.com/content/mp4/web01/2017/05/08/24599/mp4_web01.mp4" type="video/mp4" data-label="Laag - 360p" /><source src="https://download.foobar.com/content/mp4/web02/2017/05/08/24599/mp4_web02.mp4" type="video/mp4" data-label="Hoog - 720p" /><source src="https://download.foobar.com/content/mp4/web03/2017/05/08/24599/mp4_web03.mp4" type="video/mp4" data-label="Normaal - 480p" /></video></div></div>
the part I need to extract from this line is:
https://download.foobar.com/content/mp4/web02/2017/05/08/24599/mp4_web02.mp4
Now I can do a grep like this but that gives me back three lines:
grep -Po '><source src="\K[^"]+' output.txt
gives me:
https://download.omroep.nl/nos/content/mp4/web01/2017/05/08/24599/mp4_web01.mp4
https://download.omroep.nl/nos/content/mp4/web02/2017/05/08/24599/mp4_web02.mp4
https://download.omroep.nl/nos/content/mp4/web03/2017/05/08/24599/mp4_web03.mp4
I would like to get only the line I am looking for without making the extra sed command to remove the first and third line of the results.
How can I grep the input line and only get back the intended line. I only need the link to the mp4_web02.mp4 file.
Can anyone help me get this into one grep command?
there is a log file that I need to capture specific lines in, and send a specific word out of it to a url
This line does the job of tracing that log file and finding that word
tail -f /var/log/mail.log | awk '/status=bounced/ { sub(/^to=</,"",$7); sub(/>,$/,"",$7); print $7}'
Now, I need the result of $7 to be sent to some url, I'm assuming by using curl.
Assuming that this log file will only get bigger and that this script will need to run endlessly in the background..
What's the best way of putting a bash script that will answer those needs?
Thanks!
I have a 2GB text file on my linux box that I'm trying to import into my database.
The problem I'm having is that the script that is processing this rdf file is choking on one line:
mismatched tag at line 25462599, column 2, byte 1455502679:
<link r:resource="http://www.epuron.de/"/>
<link r:resource="http://www.oekoworld.com/"/>
</Topic>
=^
I want to replace the </Topic> with </Line>. I can't do a search/replace on all lines but I do have the line number so I'm hoping theres some easy way to just replace that one line with the new text.
Any ideas/suggestions?
sed -i yourfile.xml -e '25462599s!</Topic>!</Line>!'
sed -i '25462599 s|</Topic>|</Line>|' nameoffile.txt
The tool for editing text files in Unix, is called ed (as opposed to sed, which as the name implies is a stream editor).
ed was once intended as an interactive editor, but it can also easily scripted. The way ed works, is that all commands take an address parameter. The way to address a specific line is just the line number, and the way to change the addressed line(s) is the s command, which takes the same regexp that sed would. So, to change the 42nd line, you would write something like 42s/old/new/.
Here's the entire command:
FILENAME=/path/to/whereever
LINENUMBER=25462599
ed -- "${FILENAME}" <<-HERE
${LINENUMBER}s!</Topic>!</Line>!
w
q
HERE
The advantage of this is that ed is standardized, while the -i flag to sed is a proprietary GNU extension that is not available on a lot of systems.
Use "head" to get the first 25462598 lines and use "tail" to get the remaining lines (starting at 25462601). Though... for a 2GB file this will likely take a while.
Also are you sure the problem is just with that line and not somewhere previous (ie. the error looks like an XML parse error which might mean the actual problem is someplace else).
My shell script:
#!/bin/bash
awk -v line=$1 -v new_content="$2" '{
if (NR == line) {
print new_content;
} else {
print $0;
}
}' $3
Arguments:
first: line number you want change
second: text you want instead original line contents
third: file name
This script prints output to stdout then you need to redirect. Example:
./script.sh 5 "New fifth line text!" file.txt
You can improve it, for example, by taking care that all your arguments has expected values.