What is the difference on Ubuntu between awk and awk -F? For example to display the frequency of the cpu core 0 we use the command
cat /proc/cpuinfo | grep -i "^ cpu MHz" | awk -F ":" '{print $ 2}' | head -1
But why it uses awk -F? We could put awk without the -F and it would work of course (already tested).
Because without -F , we couldn't find from wath separator i will begin the calculation and print the right result. It's like a way to specify the kind of separator for this awk's using. Without it, it will choose the trivial separator in the line like if i type on the terminal: ps | grep xeyes | awk '{print $1}' ; in this case it will choose the space ' ' as a separator to print the first value: pid OF the process xeyes. I found it in https://www.shellunix.com/awk.html. Thanks for all.
I have a log file that looks like this:
RPT_LINKS=1,T1999
RPT_NUMALINKS=1
RPT_ALINKS=1,1999TK,2135,2009,31462,29467,2560
RPT_TXKEYED=1
RPT_ETXKEYED=0
I have used grep to isolate the line I am interested in with the RPT_ALINKS. In that line I want to know how to use AWK to print only the link that ends with a TK.
I am really close running this:
grep -w 'RPT_ALINKS' stats2.log | awk -F 'TK' '{print FS }'
But I am sure those who are smarter than me already know I am getting only the TK back, how do I get the entire field so that I would get a return of 1999TK?
If there is only a single RT in that line and RT is always at the end:
awk '/RPT_ALINKS/{match($0,/[^=,]*TK/); print substr($0,RSTART,RLENGTH)}'
You can also use a double grep
grep -w 'RPT_ALINKS' stats2.log | grep -wo '[^=,]*TK'
The following sed solution also works nicely:
sed '/RPT_ALINKS/s/\(^.*[,=]\)\([^=,]*TK\)\(,.*\)\?/\2/'
It doesn't get any more elegant
awk -F '=' '$1=="RPT_ALINKS" {n=split($2,array,",")
for(i=1; i<=n; i++)
if (array[i] ~ /TK$/)
{print array[i]}}
' stats2.log
n=split($2,array,","): split 1,1999TK,2135,2009,31462,29467,2560 with , to array array. n contains number of array elements, here 7.
Here is a simple solution
awk -F ',|=' '/^RPT_ALINKS/ { for (i=1; i<=NF; i++) if ($i ~ /TK$/) print $i }' stats2.log
It looks only on the record which begins with RPT_ALINKS. And there it check every field. If field ends with TK, then it prints it.
Dang, I was just about to post the double-grep alternative, but got scooped. And all the good awk solutions are taken as well.
Sigh. So here we go in bash, for fun.
$ mapfile a < stats2.log
$ for i in "${a[#]}"; do [[ $i =~ ^RPT_ALINKS=(.+,)*([^,]+TK) ]] && echo "${BASH_REMATCH[2]}"; done
1999TK
This has the disadvantage of running way slower than awk and not using fields. Oh, and it won't handle multiple *TK items on a single line. And like sed, this is processing lines as patterns rather than fields, which saps elegance. And by using mapfile, we limit the size of input you can handle because your whole log is loaded into memory. Of course you don't really need to do that, but if you were going to use a pipe, you'd use a different tool anyway. :-)
Happy Thursday.
With a sed that has -E for EREs, e.g. GNU or OSX/BSD sed:
$ sed -En 's/^RPT_ALINKS=(.*,)?([^,]*TK)(,.*|$)/\2/p' file
1999TK
With GNU awk for the 3rd arg to match():
$ awk 'match($0",",/^RPT_ALINKS=(.*,)?([^,]*TK),.*/,a){print a[2]}' file
1999TK
Instead of looping through it, you can use an other alternative.
This will be fast, loop takes time.
awk -F"TK" '/RPT_ALINKS/ {b=split($1,a,",");print a[b]FS}' stats2.log
1999TK
Here you split the line by setting field separator to TK and search for line that contains RPT_ALINKS
That gives $1=RPT_ALINKS=1,1999 and $2=,2135,2009,31462,29467,2560
$1 will always after last comma have our value.
So split it up using split function by comma. b would then contain number of fields.
Since we know that number would be in last section we do use a[b] and add FS that contains TK
I`m working on a set of data for which I need specific fields as output:
The data looks like this:
/home/oracle/db.log.gz:2013-1-19T00:00:25 <user.info> 1 2013-1-19T00:00:53.911 host_name RT_FLOW [junos#26.1.1.1.2.4 source-address="10.1.2.0" source-port="616" destination-address="100.1.1.2" destination-port="23" service-name="junos-telnet" nat-source-address="20x.2x.1.2" nat-source-port="3546" nat-destination-address="9x.12x.3.0"]
From above I need three things:
(I) - 2013-1-19T00:00:53.911 which is $4
(II)- source-address="10.1.2.0" which is $8 of which I need only 10.1.2.0
(III) - destination-address="100.1.1.2" which $10 of which I need only 100.1.1.2
I cannot use simple awk like this -> awk '{ print $4 \t $8 \t $10 }' since there are some fields after "device_name" in the log file which are not always present in all log lines so I have to make use of delimiters such as
awk -F 'source-address=' '{print $2}' | awk '{print $1} -> this gives source-addressIP which is (II) requirement
I`m not sure how do I combine using a awk search for I and II and III.
Can someone help?
I believe sed is better for this job
sed -r 's/([^ ]+[ ]+){3}([^ ]+).*[ ]+source-address="([^"]+)".*[ ]+destination-address="([^"]+)".*/\2\t\3\t\4/' file
Output:
2013-1-19T00:00:53.911 10.1.2.0 100.1.1.2
What do you exactly want?
solve the problem using any (reasonably standard) tool
solve this challenge using one instance of awk
solve the problem using just awk, no matter how many instances it costs
For the first case, you could parse the line using scripting language of your choice (mine would be Perl), or do it the hard way using sed and a single big substitution. Or something between the two – use three regexes to get the parts you want.
For the second case, you could adapt any of the former solutions, preferably the sed one. Awk and sed solutions have already been posted.
For the third case, you could just run the obvious awk solutions you mentioned in your question and send the results to a single pipe like { awk …; awk …; awk …; } < file | consumer.
Try doing this :
awk '{print gensub(/.*\s+([0-9]{4}-[0-9]+-[0-9]+T[0-9]{2}:[0-9]{2}:[0-9]{2}.[0-9]+).*source-address="([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}).*destination-address="([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}).*/, "(I) \\1\n(II) \\2\n(III) \\3", "g"); }' file
Another solution using perl :
perl -lne 'print "(", "I" x ++$c, ") $_" for m/.*?\s+(\d{4}-\d+-\d+T\d{2}:\d{2}:\d{2}.\d+).*source-address="(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}).*destination-address="(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}).*/' file
Outputs :
(I) 2013-1-19T00:00:53.911
(II) 10.1.2.0
(III) 100.1.1.2
I am stuck at getting a right solution using awk to extract versions between "[]" from
Version Repository Repository URL
[1.0.0.44] repo-0 file://test/test-1.0.0.44-features.xml
[1.0.0.21] repo-0 file://test/test-1.0.0.21-features.xml
Is there any quick efficient one-liners anyone can help with please?
With awk, using square brackets as the field separators, output field 2 except for record number 1:
awk -F '[][]' 'NR > 1 {print $2}'
Or, grep with -o is useful for extracting substrings
grep -oP '(?<=\[)[^]]+'
In the following awk command
awk '{sum+=$1; ++n} END {avg=sum/n; print "Avg monitoring time = "avg}' file.txt
what should I change to remove scientific notation output (very small values displayed as 1.5e-05) ?
I was not able to succeed with the OMFT variable.
You should use the printf AWK statement. That way you can specify padding, precision, etc. In your case, the %f control letter seems the more appropriate.
I was not able to succeed with the OMFT variable.
It is actually OFMT (outputformat), so for example:
awk 'BEGIN{OFMT="%f";print 0.000015}'
will output:
0.000015
as opposed to:
awk 'BEGIN{print 0.000015}'
which output:
1.5e-05
GNU AWK manual says that if you want to be POSIX-compliant it should be floating-point conversion specification.
Setting -v OFMT='%f' (without having to embed it into my awk statement) worked for me in the case where all I wanted from awk was to sum columns of arbitrary floating point numbers.
As the OP found, awk produces exponential notation with very small numbers,
$ some_accounting_widget | awk '{sum+=$0} END{print sum+0}'
8.992e-07 # Not useful to me
Setting OFMT for fixed that, but also rounded too aggressively,
$ some_accounting_widget | awk -v OFMT='%f' '{sum+=$0} END{print sum+0}'
0.000001 # Oops. Rounded off too much. %f rounds to 6 decimal places by default.
Specifying the number of decimal places got me what I needed,
$ some_accounting_widget | awk -v OFMT='%.10f' '{sum+=$0} END{print sum+0}'
0.0000008992 # Perfect.