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Running service --status-all | grep "firestarter" in Ubuntu shows the entire output of service --status-all with the text "firestarter" highlighted in red. How do you get grep to only show the line that contains the matched text, and hide everything else?
Maybe service --status-all writes to stderr, not stdout? Then you can use
service --status-all 2>&1 | grep firestarter
You must have some weird env variables set. Try this:
service --status-all | `which grep` firestarter
Or:
service --status-all | /bin/grep firestarter
And show the output of env and alias if possible so we can see whats wrong with your grep command.
For me, I have:
[ 13:55 jon#host ~ ]$ echo $GREP_OPTIONS
--color=always
You probably have something set there, and/or in GREP_COLOR that is causing this.
if you don't want to use an alias, but the original command, you could try "\cmd". e.g.
service --status-all | \grep "firestarter"
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I'm new to bash scripting, can someone tell me what is the meaning of the below command.
grep -v _1_ <file_name> > <new_file>
The -v switch inverts the criteria, so it shows only the lines which does NOT contain the string _1_ and logs the output into the file <new_file>.
The question is wrong, you have written the command as:
grep -v _1_ <file_name> > <new_file>
While it should be:
grep -v _1_ <file1> > <file2>
You can use grep on more file than one, which means that you are looking for something in more than one file.
The -v part is already explained by Antonio.
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Here's my config file
#comment 1
--longoption1
#comment 2
--longoption2
#comment 3
-s
#comment 4
--longoption4
I want to write a bash script that will read this .conf file, skip comments and serialize the commandline options like so.
./binary --longoption1 --longoption2 -s --longoption4
Working off of this post on sed, you just need to pipe the output from sed to xargs:
sed -e 's/#.*$//' -e '/^$/d' inputFile | xargs ./binary
As Wiimm points out, xargs can be finicky with a lot of arguments and it might split it up across multiple calls to binary. It may be better off to use sed directly:
./binary $(sed -e 's/#.*$//' -e '/^$/d' inputFile)
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how can I extract a log based on specific time frame? Let's say issue started between 4pm to 5pm, how can I get that specific log between those times? I can use less or cat or grep but it would not give me the details of the error, sample command:
grep "2013-08-26 16:00:00" sample.log
what is the more precise Linux/ Unix command that can do the trick?
For viewing ERROR log messages between 16:00:00 and 17:00:00 use:
grep -nP '2013-08-15 16:.+ERROR' sample.log | less
If you have multiline messages in log you can use -A n and -B n params to add for each output string n lines after or before:
3 lines before and after each line:
grep -A 3 -B 3 -nP '2013-08-15 16:.+ERROR' sample.log | less
Shorthand for the same:
grep -3 -nP '2013-08-15 16:.+ERROR' sample.log | less
If you know that issue happened between 4 and 5 pm, you can use this:
grep "2013-08-26 16:" sample.log | less
If you need some lines around that issue, add option -N to grep (context of N lines), something like that:
grep -3 "2013-08-26 16:" sample.log | less
If you know that your event contained some specific word, you can filter it more using one more grep:
grep -3 "2013-08-26 16:" sample.log | grep somethingelse
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My requirement is to play an alert (Play Sound) in putty if any Exception occurs in the Application , so for this purpose i have tried the below way
tail -f flex.log | grep "Exception" --color paplay alert.wav
But even though the word Exception occurs in flex Log File during tail , but it is not playing the sound .
Please let me know if there is any mistake in the above command .
I am using centOS 8 as OS and script is bash .
This will find all words with Exception and replace it with the bell character, your terminal should beep/flash/whatever you've set up to happen during a terminal bell.
tail -f flex.log | grep "Exception" | sed -e $'s/Exception/Exception\a/'
To see ALL lines of flex.log but bell only on "Exception":
tail -f flex.log | sed -e $'s/Exception/Exception\a/'
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I am using below command to send some strings to udp listening server.
echo "A 192.168.192.168" | nc -u 192.168.2.1 1234
but the server is getting trailing '\n' in echoed string.
I have tried below command too, but failed
echo "A 192.168.192.168" | nc -uC 192.168.2.1 1234
How can I remove that trailing new line character ??
Do I have any special option in nc ??
echo usually provides -n flag. This is not standard.
string A string to be written to standard output. If the first operand is -n, or if any of the operands contain a backslash ( '\' ) char‐
acter, the results are implementation-defined.
On XSI-conformant systems, if the first operand is -n, it shall be treated as a string, not an option.
I would suggest using printf
printf "A 192.168.192.168" | nc -u 192.168.2.1 1234
printf doesnt append a new line unless it is told to, and it's standard behavior.
Try using
echo -n
so
echo -n "A 192.168.192.168" | nc -u 192.168.2.1 1234
echo man page says: -n do not output the trailing newline