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I have the following string:
load Add 20 percent
to accommodate
I want to get to:
load Add 20 percent to accommodate
With, e.g., regex in sublime, this is easily done by:
Regex:
([a-z])\n\s([a-z])
Replace:
$1 $2
However, in Perl, if I input this command, (adapted to test if I can match the pattern in any case):
perl -pi.orig -e 's/[a-z]\n.+to/TEST/g' file
It doesn't match anything.
Does anyone know why Perl would be different in this case, and what the correct formulation of the Perl command should be?
By default, Perl -p flag read input lines one by one. You can't thus expect your regex to match anything after \n.
Instead, you want to read the whole input at once. You can do this by using the flag -0777 (this is documented in perlrun):
perl -0777 -pi.orig -e 's/([a-z])\n\s(to)/$1 $2/' file
Just trying to help and reminding below your initial proposal for perl regex:
perl -pi.orig -e 's/[a-z]\n.+to/TEST/g' file
Note that in perl regex, [a-z] will match only one character, NOT including any whitespace. Then as a start please include a repetition specifier and include capability to also 'eat' whitespaces. Also to keep the recognized (but 'eaten') 'to' in the replacement, you must put it again in the replacement string, like finally in the below example perl program:
$str = "load Add 20 percent
to accommodate";
print "before:\n$str\n";
$str =~ s/([ a-z]+)\n\s*to/\1 to/;
print "after:\n$str\n";
This program produces the below input:
before:
load Add 20 percent
to accommodate
after:
load Add 20 percent to accommodate
Then it looks like that if I understood well what you want to do, your regexp should better look like:
s/([ a-z]+)\n\s*to/\1 to/ (please note the leading whitespace before 'a-z').
I want to use grep/awk/sed to extract matched strings for each line of a log file. Then place it into csv file.
Highlighted strings (1432,53,http://www.espn.com/)
If the input is:
2018-10-31
18:48:01.717,INFO,15592.15627,PfbProxy::handlePfbFetchDone(0x1d69850,
pfbId=561, pid=15912, state=4, fd=78, timer=61), FETCH DONE: len=45,
PFBId=561, pid=0, loadTime=1434 ms, objects=53, fetchReqEpoch=0.0,
fetchDoneEpoch:0.0, fetchId=26, URL=http://www.espn.com/
2018-10-31
18:48:01.806,DEBUG,15592.15621,FETCH DONE: len=45, PFBId=82, pid=0,
loadTime=1301 ms, objects=54, fetchReqEpoch=0.0, fetchDoneEpoch:0.0,
fetchId=28, URL=http://www.diply.com/
Expected output for the above log lines:
URL,LoadTime,Objects
http://www.espn.com/,1434,53
http://www.diply.com/,1301,54
This is an example, and the actual Log File will have much more data.
--My-Solution-So-far-
For now I used grep to get all lines containing keyword 'FETCH DONE' (these lines contain strings I am looking for).
I did come up with regular expression that matches the data I need, but when I grep it and put it in the file it prints each string on the new line which is not quite what I am looking for.
The grep and regular expression I use (online regex tool: https://regexr.com/42cah):
echo -en 'url,loadtime,object\n'>test1.csv #add header
grep -Po '(?<=loadTime=).{1,5}(?= )|((?<=URL=).*|\/(?=.))|((?<=objects=).{1,5}(?=\,))'>>test1.csv #get matching strings
Actual output:
URL,LoadTime,Objects
http://www.espn.com
1434
53
http://www.diply.com
1301
54
Expected output:
URL,LoadTime,Objects
http://www.espn.com/,1434,53
http://www.diply.com/,1301,54
I was trying using awk to match multiple regex and print comma in between. I couldn't get it to work at all for some reason, even though my regex matches correct strings.
Another idea I have is to use sed to replace some '\n' for ',':
for(i=1;i<=n;i++)
if(i % 3 != 0){
sed REPLACE "\n" with "," on i-th line
}
Im pretty sure there is a more efficient way of doing it
Using sed:
sed -n 's/.*loadTime=\([0-9]*\)[^,]*, objects=\([0-9]*\).* URL=\(.*\)/\3,\1,\2/p' input | \
sed 1i'URL,LoadTime,Objects'
I have a file that contains lines in a format similar to this...
/data/file.geojson?10,20,30,40
/data/file.geojson?bbox=-5.20751953125,49.05227025601607,3.0322265625,56.46249048388979
/data/file.geojson?bbox=-21.46728515625,45.99696161820381,19.2919921875,58.88194208135912
/data/file.geojson?bbox=-2.8482055664062496,54.38935426009769,-0.300750732421875,55.158473983815306
/data/file.geojson?bbox=-21.46728515625,45.99696161820381,19.2919921875,58.88194208135912
/data/file.geojson?bbox=-21.46728515625,45.99696161820381,19.2919921875,58.88194208135912
I've tried a combination of grep, sed, gawk, and |(pipes) to try and pattern match and then change the format to be more like this...
[10,40],[30,40],[30,20][10,20],
[-5.20751953125,56.46249048388979],[3.0322265625,56.46249048388979].....
Hopefully you get the idea from the first line so I don't have to type out all the examples manually!
I've got the hang of regex to match the co-ordinates. In fact the input file is the result of extracting from apache access logs. It might be easier to read/understand answers if they just match positive integer numbers, I will then be able to slot in a more complicated pattern to match the right range.
To be able to arrange the results like you which it is important to be able to access the last for values per line.
No pattern matching is required if you use awk. You can split the input strings by a set of delimiters and reassemble the resulting fields. 40 can be accessed as $(NF), 30 as $(NF-1) and so on.
awk -F'[?,=]' '
{printf "[%s,%s],[%s,%s],[%s,%s],[%s,%s]\n",
$(NF-3),$(NF),$(NF-1),$(NF),
$(NF-1),$(NF-2),$(NF-3),$(NF-2)
}' file
I'm using ?, , or = as the field delimiters. This makes it simple to access the columns of interest.
Output:
[10,40],[30,40],[30,20],[10,20]
[-5.20751953125,56.46249048388979],[3.0322265625,56.46249048388979],[3.0322265625,49.05227025601607],[-5.20751953125,49.05227025601607]
[-21.46728515625,58.88194208135912],[19.2919921875,58.88194208135912],[19.2919921875,45.99696161820381],[-21.46728515625,45.99696161820381]
[-2.8482055664062496,55.158473983815306],[-0.300750732421875,55.158473983815306],[-0.300750732421875,54.38935426009769],[-2.8482055664062496,54.38935426009769]
[-21.46728515625,58.88194208135912],[19.2919921875,58.88194208135912],[19.2919921875,45.99696161820381],[-21.46728515625,45.99696161820381]
[-21.46728515625,58.88194208135912],[19.2919921875,58.88194208135912],[19.2919921875,45.99696161820381],[-21.46728515625,45.99696161820381]
Btw, also sed can be used here:
sed -r 's/.*[?=]([^,]+),([^,]+),([^,]+),(.*)/[\1,\4],[\3,\4],[\3,\2],[\1,\2]/' file
The command is capturing the numbers at the end each in a separate capturing group and re-assembles them in the replacement part.
Not all versions of sed support the + quantifier. The most compatible version would look like this :)
sed 's/.*[?=]\([^,]\{1,\}\),\([^,]\{1,\}+\),\([^,]\{1,\}\),\(.*\)/[\1,\4],[\3,\4],[\3,\2],[\1,\2]/' file
sed strips off items prior to numbers, then awk splits on comma and outputs in different order. Assuming data is in a file called "td.txt"
sed 's/^[^0-9-]*//' td.txt|awk -F, '{print "["$1","$4"],["$3","$4"],["$3","$2"],["$1","$2"],"}'
This might work for you (GNU sed):
sed -r 's/^.*\?[^-0-9]*([^,]*),([^,]*),([^,]*),([^,]*)/[\1,\4],[\3,\4],[\3,\2],[\1,\2]/' file
Or with more toothpicks:
sed 's/^.*\?[^-0-9]*\([^,]*\),\([^,]*\),\([^,]*\),\([^,]*\)/[\1,\4],[\3,\4],[\3,\2],[\1,\2]/' file
You can use the following to match:
(\/data\/file\.geojson\?(?:bbox=)?)([0-9.-]+),([0-9.-]+),([0-9.-]+),([0-9.-]+)
And replace with the following:
$1[$2,$3],[$4,$5]
See DEMO
I see lots of examples and man pages on how to do things like search-and-replace using sed, awk, or gawk.
But in my case, I have a regular expression that I want to run against a text file to extract a specific value. I don't want to do search-and-replace. This is being called from bash. Let's use an example:
Example regular expression:
.*abc([0-9]+)xyz.*
Example input file:
a
b
c
abc12345xyz
a
b
c
As simple as this sounds, I cannot figure out how to call sed/awk/gawk correctly. What I was hoping to do, is from within my bash script have:
myvalue=$( sed <...something...> input.txt )
Things I've tried include:
sed -e 's/.*([0-9]).*/\\1/g' example.txt # extracts the entire input file
sed -n 's/.*([0-9]).*/\\1/g' example.txt # extracts nothing
My sed (Mac OS X) didn't work with +. I tried * instead and I added p tag for printing match:
sed -n 's/^.*abc\([0-9]*\)xyz.*$/\1/p' example.txt
For matching at least one numeric character without +, I would use:
sed -n 's/^.*abc\([0-9][0-9]*\)xyz.*$/\1/p' example.txt
You can use sed to do this
sed -rn 's/.*abc([0-9]+)xyz.*/\1/gp'
-n don't print the resulting line
-r this makes it so you don't have the escape the capture group parens().
\1 the capture group match
/g global match
/p print the result
I wrote a tool for myself that makes this easier
rip 'abc(\d+)xyz' '$1'
I use perl to make this easier for myself. e.g.
perl -ne 'print $1 if /.*abc([0-9]+)xyz.*/'
This runs Perl, the -n option instructs Perl to read in one line at a time from STDIN and execute the code. The -e option specifies the instruction to run.
The instruction runs a regexp on the line read, and if it matches prints out the contents of the first set of bracks ($1).
You can do this will multiple file names on the end also. e.g.
perl -ne 'print $1 if /.*abc([0-9]+)xyz.*/' example1.txt example2.txt
If your version of grep supports it you could use the -o option to print only the portion of any line that matches your regexp.
If not then here's the best sed I could come up with:
sed -e '/[0-9]/!d' -e 's/^[^0-9]*//' -e 's/[^0-9]*$//'
... which deletes/skips with no digits and, for the remaining lines, removes all leading and trailing non-digit characters. (I'm only guessing that your intention is to extract the number from each line that contains one).
The problem with something like:
sed -e 's/.*\([0-9]*\).*/&/'
.... or
sed -e 's/.*\([0-9]*\).*/\1/'
... is that sed only supports "greedy" match ... so the first .* will match the rest of the line. Unless we can use a negated character class to achieve a non-greedy match ... or a version of sed with Perl-compatible or other extensions to its regexes, we can't extract a precise pattern match from with the pattern space (a line).
You can use awk with match() to access the captured group:
$ awk 'match($0, /abc([0-9]+)xyz/, matches) {print matches[1]}' file
12345
This tries to match the pattern abc[0-9]+xyz. If it does so, it stores its slices in the array matches, whose first item is the block [0-9]+. Since match() returns the character position, or index, of where that substring begins (1, if it starts at the beginning of string), it triggers the print action.
With grep you can use a look-behind and look-ahead:
$ grep -oP '(?<=abc)[0-9]+(?=xyz)' file
12345
$ grep -oP 'abc\K[0-9]+(?=xyz)' file
12345
This checks the pattern [0-9]+ when it occurs within abc and xyz and just prints the digits.
perl is the cleanest syntax, but if you don't have perl (not always there, I understand), then the only way to use gawk and components of a regex is to use the gensub feature.
gawk '/abc[0-9]+xyz/ { print gensub(/.*([0-9]+).*/,"\\1","g"); }' < file
output of the sample input file will be
12345
Note: gensub replaces the entire regex (between the //), so you need to put the .* before and after the ([0-9]+) to get rid of text before and after the number in the substitution.
If you want to select lines then strip out the bits you don't want:
egrep 'abc[0-9]+xyz' inputFile | sed -e 's/^.*abc//' -e 's/xyz.*$//'
It basically selects the lines you want with egrep and then uses sed to strip off the bits before and after the number.
You can see this in action here:
pax> echo 'a
b
c
abc12345xyz
a
b
c' | egrep 'abc[0-9]+xyz' | sed -e 's/^.*abc//' -e 's/xyz.*$//'
12345
pax>
Update: obviously if you actual situation is more complex, the REs will need to me modified. For example if you always had a single number buried within zero or more non-numerics at the start and end:
egrep '[^0-9]*[0-9]+[^0-9]*$' inputFile | sed -e 's/^[^0-9]*//' -e 's/[^0-9]*$//'
The OP's case doesn't specify that there can be multiple matches on a single line, but for the Google traffic, I'll add an example for that too.
Since the OP's need is to extract a group from a pattern, using grep -o will require 2 passes. But, I still find this the most intuitive way to get the job done.
$ cat > example.txt <<TXT
a
b
c
abc12345xyz
a
abc23451xyz asdf abc34512xyz
c
TXT
$ cat example.txt | grep -oE 'abc([0-9]+)xyz'
abc12345xyz
abc23451xyz
abc34512xyz
$ cat example.txt | grep -oE 'abc([0-9]+)xyz' | grep -oE '[0-9]+'
12345
23451
34512
Since processor time is basically free but human readability is priceless, I tend to refactor my code based on the question, "a year from now, what am I going to think this does?" In fact, for code that I intend to share publicly or with my team, I'll even open man grep to figure out what the long options are and substitute those. Like so: grep --only-matching --extended-regexp
why even need match group
gawk/mawk/mawk2 'BEGIN{ FS="(^.*abc|xyz.*$)" } ($2 ~ /^[0-9]+$/) {print $2}'
Let FS collect away both ends of the line.
If $2, the leftover not swallowed by FS, doesn't contain non-numeric characters, that's your answer to print out.
If you're extra cautious, confirm length of $1 and $3 both being zero.
** edited answer after realizing zero length $2 will trip up my previous solution
there's a standard piece of code from awk channel called "FindAllMatches" but it's still very manual, literally, just long loops of while(), match(), substr(), more substr(), then rinse and repeat.
If you're looking for ideas on how to obtain just the matched pieces, but upon a complex regex that matches multiple times each line, or none at all, try this :
mawk/mawk2/gawk 'BEGIN { srand(); for(x = 0; x < 128; x++ ) {
alnumstr = sprintf("%s%c", alnumstr , x)
};
gsub(/[^[:alnum:]_=]+|[AEIOUaeiou]+/, "", alnumstr)
# resulting str should be 44-chars long :
# all digits, non-vowels, equal sign =, and underscore _
x = 10; do { nonceFS = nonceFS substr(alnumstr, 1 + int(44*rand()), 1)
} while ( --x ); # you can pick any level of precision you need.
# 10 chars randomly among the set is approx. 54-bits
#
# i prefer this set over all ASCII being these
# just about never require escaping
# feel free to skip the _ or = or r/t/b/v/f/0 if you're concerned.
#
# now you've made a random nonce that can be
# inserted right in the middle of just about ANYTHING
# -- ASCII, Unicode, binary data -- (1) which will always fully
# print out, (2) has extremely low chance of actually
# appearing inside any real word data, and (3) even lower chance
# it accidentally alters the meaning of the underlying data.
# (so intentionally leaving them in there and
# passing it along unix pipes remains quite harmless)
#
# this is essentially the lazy man's approach to making nonces
# that kinda-sorta have some resemblance to base64
# encoded, without having to write such a module (unless u have
# one for awk handy)
regex1 = (..); # build whatever regex you want here
FS = OFS = nonceFS;
} $0 ~ regex1 {
gsub(regex1, nonceFS "&" nonceFS); $0 = $0;
# now you've essentially replicated what gawk patsplit( ) does,
# or gawk's split(..., seps) tracking 2 arrays one for the data
# in between, and one for the seps.
#
# via this method, that can all be done upon the entire $0,
# without any of the hassle (and slow downs) of
# reading from associatively-hashed arrays,
#
# simply print out all your even numbered columns
# those will be the parts of "just the match"
if you also run another OFS = ""; $1 = $1; , now instead of needing 4-argument split() or patsplit(), both of which being gawk specific to see what the regex seps were, now the entire $0's fields are in data1-sep1-data2-sep2-.... pattern, ..... all while $0 will look EXACTLY the same as when you first read in the line. a straight up print will be byte-for-byte identical to immediately printing upon reading.
Once i tested it to the extreme using a regex that represents valid UTF8 characters on this. Took maybe 30 seconds or so for mawk2 to process a 167MB text file with plenty of CJK unicode all over, all read in at once into $0, and crank this split logic, resulting in NF of around 175,000,000, and each field being 1-single character of either ASCII or multi-byte UTF8 Unicode.
you can do it with the shell
while read -r line
do
case "$line" in
*abc*[0-9]*xyz* )
t="${line##abc}"
echo "num is ${t%%xyz}";;
esac
done <"file"
For awk. I would use the following script:
/.*abc([0-9]+)xyz.*/ {
print $0;
next;
}
{
/* default, do nothing */
}
gawk '/.*abc([0-9]+)xyz.*/' file
I have an HTML file and would like to extract the text between <li> and </li> tags. There are of course a million ways to do this, but I figured it would be useful to get more into the habit of doing this in simple shell commands:
awk '/<li[^>]+><a[^>]+>([^>]+)<\/a>/m' cities.html
The problem is, this prints everything whereas I simply want to print the match in parenthesis -- ([^>]+) -- either awk doesn't support this, or I'm incompetent. The latter seems more likely. If you wanted to apply the supplied regex to a file and extract only the specified matches, how would you do it? I already know a half dozen other ways, but I don't feel like letting awk win this round ;)
Edit: The data is not well-structured, so using positional matches ($1, $2, etc.) is a no-go.
If you want to do this in the general case, where your list tags can contain any legal HTML markup, then awk is the wrong tool. The right tool for the job would be an HTML parser, which you can trust to get correct all of the little details of HTML parsing, including variants of HTML and malformed HTML.
If you are doing this for a special case, where you can control the HTML formatting, then you may be able to make awk work for you. For example, let's assume you can guarantee that each list element never occupies more than one line, is always terminated with </li> on the same line, never contains any markup (such as a list that contains a list), then you can use awk to do this, but you need to write a whole awk program that first finds lines that contain list elements, then uses other awk commands to find just the substring you are interested in.
But in general, awk is the wrong tool for this job.
gawk -F'<li>' -v RS='</li>' 'RT{print $NF}' file
Worked pretty well for me.
By your script, if you can get what you want (it means <li> and <a> tag is in one line.);
$ cat test.html | awk 'sub(/<li[^>]*><a[^>]*>/,"")&&sub(/<\/a>.*/,"")'
or
$ cat test.html | gawk '/<li[^>]*><a[^>]*>(.*?)<\/a>.*/&&$0=gensub(/<li[^>]*><a[^>]*>(.*?)<\/a>.*/,"\\1", 1)'
First one is for every awk, second one is for gnu awk.
There are several issues that I see:
The pattern has a trailing 'm' which is significant for multi-line matches in Perl, but Awk does not use Perl-compatible regular expressions. (At least, standard (non-GNU) awk does not.)
Ignoring that, the pattern seems to search for a 'start list item' followed by an anchor '<a>' to '</a>', not the end list item.
You search for anything that is not a '>' as the body of the anchor; that's not automatically wrong, but it might be more usual to search for anything that is not '<', or anything that is neither.
Awk does not do multi-line searches.
In Awk, '$1' denotes the first field, where the fields are separated by the field separator characters, which default to white space.
In classic nawk (as documented in the 'sed & awk' book vintage 1991) does not have a mechanism in place for pulling sub-fields out of matches, etc.
It is not clear that Awk is the right tool for this job. Indeed, it is not entirely clear that regular expressions are the right tool for this job.
Don't really know awk, how about Perl instead?
tr -d '\012' the.html | perl \
-e '$text = <>;' -e 'while ( length( $text) > 0)' \
-e '{ $text =~ /<li>(.*?)<\/li>(.*)/; $target = $1; $text = $2; print "$target\n" }'
1) remove newlines from file, pipe through perl
2) initialize a variable with the complete text, start a loop until text is gone
3) do a "non greedy" match for stuff bounded by list-item tags, save and print the target, set up for next pass
Make sense? (warning, did not try this code myself, need to go home soon...)
P.S. - "perl -n" is Awk (nawk?) mode. Perl is largely a superset of Awk, so I never bothered to learn Awk.