I need from this file extract line that starts with a number in the range 10-20 and I have tried use grep "[10-20]" tmp_file.txt, but from a file that has this format
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.aa
12.bbb
13.cccc
14.ddddd
15.eeeeee
16.fffffff
17.gggggggg
18.hhhhhhhhh
19.iiiiiiiiii
20.jjjjjjjjjjj
21.
it returned everything and marked every number that contains either 1, 0, 10, 2, 0, 20 or 21 :/
With an extended regular expression (-E):
grep -E '^(1[0-9]|20)\.' file
Output:
10.aa
12.bbb
13.cccc
14.ddddd
15.eeeeee
16.fffffff
17.gggggggg
18.hhhhhhhhh
19.iiiiiiiiii
20.jjjjjjjjjjj
See: The Stack Overflow Regular Expressions FAQ
An other one with awk
awk '/^10\./,/^20\./' tmp_file.txt
awk '/^10\./,/^13\./' tmp_file.txt
10.aa
12.bbb
13.cccc
Try
grep -w -e '^1[[:digit:]]' -e '^20' tmp_file.txt
-w forces matches of whole words. That prevents matching lines like 100.... It's not POSIX, but it's supported by every grep that most people will encounter these days. Use grep -e '^1[[:digit:]]\.' -e '^20\.' ... if you are concerned about portability.
The -e option can be used multiple times to specify multiple patterns.
[[:digit:]] may be more reliable than [0-9]. See In grep command, can I change [:digit:] to [0-9]?.
Assuming the file might not be sorted and using numeric comparison
awk -F. '$1 >= 10 && $1 <= 20' < file.txt
grep is not the tool for this, because grep finds text patterns, but does not understand numeric values. Making patterns that match the 11 values from 10-20 is like stirring a can of paint with a screwdriver. You can do it, but it's not the right tool for the job.
A much clearer way to do this is with Perl:
$ perl -n -e'print if /^(\d+)/ && $1 >= 10 && $1 <= 20' foo.txt
This says to print a line of the file if the beginning of the line ^ matches one or more digits \d+ and if the numeric value of what was matched $1 is between the values of 10 and 20.
Related
I want to run ack or grep on HTML files that often have very long lines. I don't want to see very long lines that wrap repeatedly. But I do want to see just that portion of a long line that surrounds a string that matches the regular expression. How can I get this using any combination of Unix tools?
You could use the grep options -oE, possibly in combination with changing your pattern to ".{0,10}<original pattern>.{0,10}" in order to see some context around it:
-o, --only-matching
Show only the part of a matching line that matches PATTERN.
-E, --extended-regexp
Interpret pattern as an extended regular expression (i.e., force grep to behave as egrep).
For example (from #Renaud's comment):
grep -oE ".{0,10}mysearchstring.{0,10}" myfile.txt
Alternatively, you could try -c:
-c, --count
Suppress normal output; instead print a count of matching lines
for each input file. With the -v, --invert-match option (see
below), count non-matching lines.
Pipe your results thru cut. I'm also considering adding a --cut switch so you could say --cut=80 and only get 80 columns.
You could use less as a pager for ack and chop long lines: ack --pager="less -S" This retains the long line but leaves it on one line instead of wrapping. To see more of the line, scroll left/right in less with the arrow keys.
I have the following alias setup for ack to do this:
alias ick='ack -i --pager="less -R -S"'
grep -oE ".\{0,10\}error.\{0,10\}" mylogfile.txt
In the unusual situation where you cannot use -E, use lowercase -e instead.
Explanation:
cut -c 1-100
gets characters from 1 to 100.
The Silver Searcher (ag) supports its natively via the --width NUM option. It will replace the rest of longer lines by [...].
Example (truncate after 120 characters):
$ ag --width 120 '#patternfly'
...
1:{"version":3,"file":"react-icons.js","sources":["../../node_modules/#patternfly/ [...]
In ack3, a similar feature is planned but currently not implemented.
Taken from: http://www.topbug.net/blog/2016/08/18/truncate-long-matching-lines-of-grep-a-solution-that-preserves-color/
The suggested approach ".{0,10}<original pattern>.{0,10}" is perfectly good except for that the highlighting color is often messed up. I've created a script with a similar output but the color is also preserved:
#!/bin/bash
# Usage:
# grepl PATTERN [FILE]
# how many characters around the searching keyword should be shown?
context_length=10
# What is the length of the control character for the color before and after the
# matching string?
# This is mostly determined by the environmental variable GREP_COLORS.
control_length_before=$(($(echo a | grep --color=always a | cut -d a -f '1' | wc -c)-1))
control_length_after=$(($(echo a | grep --color=always a | cut -d a -f '2' | wc -c)-1))
grep -E --color=always "$1" $2 |
grep --color=none -oE \
".{0,$(($control_length_before + $context_length))}$1.{0,$(($control_length_after + $context_length))}"
Assuming the script is saved as grepl, then grepl pattern file_with_long_lines should display the matching lines but with only 10 characters around the matching string.
I put the following into my .bashrc:
grepl() {
$(which grep) --color=always $# | less -RS
}
You can then use grepl on the command line with any arguments that are available for grep. Use the arrow keys to see the tail of longer lines. Use q to quit.
Explanation:
grepl() {: Define a new function that will be available in every (new) bash console.
$(which grep): Get the full path of grep. (Ubuntu defines an alias for grep that is equivalent to grep --color=auto. We don't want that alias but the original grep.)
--color=always: Colorize the output. (--color=auto from the alias won't work since grep detects that the output is put into a pipe and won't color it then.)
$#: Put all arguments given to the grepl function here.
less: Display the lines using less
-R: Show colors
S: Don't break long lines
Here's what I do:
function grep () {
tput rmam;
command grep "$#";
tput smam;
}
In my .bash_profile, I override grep so that it automatically runs tput rmam before and tput smam after, which disabled wrapping and then re-enables it.
ag can also take the regex trick, if you prefer it:
ag --column -o ".{0,20}error.{0,20}"
I have a string with multiple value outputs that looks like this:
SD performance read=1450kB/s write=872kB/s no error (0 0), ManufactorerID 27 Date 2014/2 CardType 2 Blocksize 512 Erase 0 MaxtransferRate 25000000 RWfactor 2 ReadSpeed 22222222Hz WriteSpeed 22222222Hz MaxReadCurrentVDDmin 3 MaxReadCurrentVDDmax 5 MaxWriteCurrentVDDmin 3 MaxWriteCurrentVDDmax 1
I would like to output only the read value (1450kB/s) using bash and sed.
I tried
sed 's/read=\(.*\)kB/\1/'
but that outputs read=1450kB but I only want the number.
Thanks for any help.
Sample input shortened for demo:
$ echo 'SD performance read=1450kB/s write=872kB/s no error' | sed 's/read=\(.*\)kB/\1/'
SD performance 1450kB/s write=872/s no error
$ echo 'SD performance read=1450kB/s write=872kB/s no error' | sed 's/.*read=\(.*\)kB.*/\1/'
1450kB/s write=872
$ echo 'SD performance read=1450kB/s write=872kB/s no error' | sed 's/.*read=\([0-9]*\)kB.*/\1/'
1450
Since entire line has to be replaced, add .* before and after search pattern
* is greedy, will try to match as much as possible, so in 2nd example it can be seen that it matched even the values of write
Since only numbers after read= is needed, use [0-9] instead of .
Running
sed 's/read=\(.*\)kB/\1/'
will replace read=[digits]kB with [digit]. If you want to replace the whole string, use
sed 's/.*read=\([0-9]*\)kB.*/\1/'
instead.
As Sundeep noticed, sed doesn't support non-greedy pattern, updated for [0-9]* instead
I'm trying to extract the last number before a file extension in a bash script. So the format varies but it'll be some combination of numbers and letters, and the last character will always be a digit. I need to pull those digits and store them in a variable.
The format is generally:
sdflkej10_sdlkei450_sdlekr_1.txt
I want to store just the final digit 1 into a variable.
I'll be using this to loop through a large number of files, and the last number will get into double and triple digits.
So for this file:
kej10_sdlkei450_sdlekr_310.txt
I'd need to return 310.
The number of alphanumeric characters and underscores varies with each file, but the number I want always is immediately before the .txt extension and immediately after an underscore.
I tried:
bname=${f%%.*}
number=$(echo $bname | tr -cd '[[:digit:]]')
but this returns all digits.
If I try
number = $(echo $(bname -2) it changes the number it returns.
The problem i'm having is mostly related to the variability, and the fact that I've been asked to do it in bash. Any help would really be appreciated.
regex='([0-9]+)\.[^.]*$'
[[ $file =~ $regex ]] && number=${BASH_REMATCH[1]}
This uses bash's underappreciated =~ regex operator which stores matches in an array named BASH_REMATCH.
You could do this using parameter substitution
var=kej10_sdlkei450_sdlekr_310.txt
var=${var%.*}
var=${var##*_}
echo $var
310
Use a Series of Bash Shell Expansions
While not the most elegant solution, this one uses a sequence of shell parameter expansions to achieve the desired result without having to define a specific extension. For example, this function uses the length and offset expansions to find the digit after removing filename extensions:
extract_digit() {
local basename=${1%%.*}
echo "${basename:$(( ${#basename} - 1 ))}"
}
Capturing Function Output
You can capture the output in a variable with something like:
$ foo=$(extract_digit sdflkej10_sdlkei450_sdlekr_1.txt)
$ echo $foo
1
Sample Output from Function
$ extract_digit sdflkej10_sdlkei450_sdlekr_1.txt
1
$ extract_digit sdflkej10_sdlkei450_sdlekr_9.txt
9
$ extract_digit sdflkej10_sdlkei450_sdlekr_10.txt
0
This should take care of your situation:
INPUT="some6random7numbers_12345_moreletters_789.txt"
SUBSTRING=`expr match "$INPUT" '.*_\([[:digit:]]*\)'`
echo $SUBSTRING
This will output 789
No need of regex here, you can utilize IFS
var="kej10_sdlkei450_sdlekr_310.txt"
v=$(IFS=[_.] read -ra arr <<< "$var" && echo "${arr[#]:(-2):1}")
echo "$v"
310
How do I remove duplicate characters and keep the unique one only.
For example, my input is:
EFUAHUU
UUUEUUUUH
UJUJHHACDEFUCU
Expected output is:
EFUAH
UEH
UJHACDEF
I came across perl -pe's/$1//g while/(.).*\/' which is wonderful but it is removing even the single occurrence of the character in output.
This can be done using positive lookahead :
perl -pe 's/(.)(?=.*?\1)//g' FILE_NAME
The regex used is: (.)(?=.*?\1)
. : to match any char.
first () : remember the matched
single char.
(?=...) : +ve lookahead
.*? : to match anything in between
\1 : the remembered match.
(.)(?=.*?\1) : match and remember
any char only if it appears again
later in the string.
s/// : Perl way of doing the
substitution.
g: to do the substitution
globally...that is don't stop after
first substitution.
s/(.)(?=.*?\1)//g : this will
delete a char from the input string
only if that char appears again later
in the string.
This will not maintain the order of the char in the input because for every unique char in the input string, we retain its last occurrence and not the first.
To keep the relative order intact we can do what KennyTM tells in one of the comments:
reverse the input line
do the substitution as before
reverse the result before printing
The Perl one line for this is:
perl -ne '$_=reverse;s/(.)(?=.*?\1)//g;print scalar reverse;' FILE_NAME
Since we are doing print manually after reversal, we don't use the -p flag but use the -n flag.
I'm not sure if this is the best one-liner to do this. I welcome others to edit this answer if they have a better alternative.
if Perl is not a must, you can also use awk. here's a fun benchmark on the Perl one liners posted against awk. awk is 10+ seconds faster for a file with 3million++ lines
$ wc -l <file2
3210220
$ time awk 'BEGIN{FS=""}{delete _;for(i=1;i<=NF;i++){if(!_[$i]++) printf $i};print""}' file2 >/dev/null
real 1m1.761s
user 0m58.565s
sys 0m1.568s
$ time perl -n -e '%seen=();' -e 'for (split //) {print unless $seen{$_}++;}' file2 > /dev/null
real 1m32.123s
user 1m23.623s
sys 0m3.450s
$ time perl -ne '$_=reverse;s/(.)(?=.*?\1)//g;print scalar reverse;' file2 >/dev/null
real 1m17.818s
user 1m10.611s
sys 0m2.557s
$ time perl -ne'my%s;print grep!$s{$_}++,split//' file2 >/dev/null
real 1m20.347s
user 1m13.069s
sys 0m2.896s
perl -ne'my%s;print grep!$s{$_}++,split//'
Here is a solution, that I think should work faster than the lookahead one, but is not regexp-based and uses hashtable.
perl -n -e '%seen=();' -e 'for (split //) {print unless $seen{$_}++;}'
It splits every line into characters and prints only the first appearance by counting appearances inside %seen hashtable
Tie::IxHash is a good module to store hash order (but may be slow, you will need to benchmark if speed is important). Example with tests:
use Test::More 0.88;
use Tie::IxHash;
sub dedupe {
my $str=shift;
my $hash=Tie::IxHash->new(map { $_ => 1} split //,$str);
return join('',$hash->Keys);
}
{
my $str='EFUAHUU';
is(dedupe($str),'EFUAH');
}
{
my $str='EFUAHHUU';
is(dedupe($str),'EFUAH');
}
{
my $str='UJUJHHACDEFUCU';
is(dedupe($str),'UJHACDEF');
}
done_testing();
Use uniq from List::MoreUtils:
perl -MList::MoreUtils=uniq -ne 'print uniq split ""'
If the set of characters that can be encountered is restricted, e.g. only letters, then the easiest solution will be with tr
perl -p -e 'tr/a-zA-Z/a-zA-Z/s'
It will replace all the letters by themselves, leaving other characters unaffected and /s modifier will squeeze repeated occurrences of the same character (after replacement), thus removing duplicates
Me bad - it removes only adjoining appearances. Disregard
This looks like a classic application of positive lookbehind, but unfortunately perl doesn't support that. In fact, doing this (matching the preceding text of a character in a string with a full regex whose length is indeterminable) can only be done with .NET regex classes, I think.
However, positive lookahead supports full regexes, so all you need to do is reverse the string, apply positive lookahead (like unicornaddict said):
perl -pe 's/(.)(?=.*?\1)//g'
And reverse it back, because without the reverse that'll only keep the duplicate character at the last place in a line.
MASSIVE EDIT
I've been spending the last half an hour on this, and this looks like this works, without the reversing.
perl -pe 's/\G$1//g while (/(.).*(?=\1)/g)' FILE_NAME
I don't know whether to be proud or horrified. I'm basically doing the positive looakahead, then substituting on the string with \G specified - which makes the regex engine start its matching from the last place matched (internally represented by the pos() variable).
With test input like this:
aabbbcbbccbabb
EFAUUUUH
ABCBBBBD
DEEEFEGGH
AABBCC
The output is like this:
abc
EFAUH
ABCD
DEFGH
ABC
I think it's working...
Explanation - Okay, in case my explanation last time wasn't clear enough - the lookahead will go and stop at the last match of a duplicate variable [in the code you can do a print pos(); inside the loop to check] and the s/\G//g will remove it [you don't need the /g really]. So within the loop, the substitution will continue removing until all such duplicates are zapped. Of course, this might be a little too processor intensive for your tastes... but so are most of the regex-based solutions you'll see. The reversing/lookahead method will probably be more efficient than this, though.
From the shell, this works:
sed -e 's/$/<EOL>/ ; s/./&\n/g' test.txt | uniq | sed -e :a -e '$!N; s/\n//; ta ; s/<EOL>/\n/g'
In words: mark every linebreak with a <EOL> string, then put every character on a line of its own, then use uniq to remove duplicate lines, then strip out all the linebreaks, then put back linebreaks instead of the <EOL> markers.
I found the -e :a -e '$!N; s/\n//; ta part in a forum post and I don't understand the seperate -e :a part, or the $!N part, so if anyone can explain those, I'd be grateful.
Hmm, that one does only consecutive duplicates; to eliminate all duplicates you could do this:
cat test.txt | while read line ; do echo $line | sed -e 's/./&\n/g' | sort | uniq | sed -e :a -e '$!N; s/\n//; ta' ; done
That puts the characters in each line in alphabetical order though.
use strict;
use warnings;
my ($uniq, $seq, #result);
$uniq ='';
sub uniq {
$seq = shift;
for (split'',$seq) {
$uniq .=$_ unless $uniq =~ /$_/;
}
push #result,$uniq;
$uniq='';
}
while(<DATA>){
uniq($_);
}
print #result;
__DATA__
EFUAHUU
UUUEUUUUH
UJUJHHACDEFUCU
The output:
EFUAH
UEH
UJHACDEF
for a file containing the data you list named foo.txt
python -c "print set(open('foo.txt').read())"
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