I have a few huge files with values seperated by a pipe (|) sign.
The strings our quoted but sometimes there is a newline in between the quoted string.
I need to read these files with external table from oracle but on the newlines he will give me errors. So I need to replace them with a space.
I do some other perl commands on these files for other errors, so I would like to have a solution in a one line perl command.
I 've found some other similar questions on stackoverflow, but they don't quite do the same and I can't find a solution for my problem with the solution mentioned there.
The statement I tried but that isn't working:
perl -pi -e 's/"(^|)*\n(^|)*"/ /g' test.txt
Sample text:
4454|"test string"|20-05-1999|"test 2nd string"
4455|"test newline
in string"||"test another 2nd string"
4456|"another string"|19-03-2021|"here also a newline
"
4457|.....
Should become:
4454|"test string"|20-05-1999|"test 2nd string"
4455|"test newline in string"||"test another 2nd string"
4456|"another string"|19-03-2021|"here also a newline "
4457|.....
Sounds like you want a CSV parser like Text::CSV_XS (Install through your OS's package manager or favorite CPAN client):
$ perl -MText::CSV_XS -e '
my $csv = Text::CSV_XS->new({sep => "|", binary => 1});
while (my $row = $csv->getline(*ARGV)) {
$csv->say(*STDOUT, [ map { tr/\n/ /r } #$row ])
}' test.txt
4454|"test string"|20-05-1999|"test 2nd string"
4455|"test newline in string"||"test another 2nd string"
4456|"another string"|19-03-2021|"here also a newline "
This one-liner reads each record using | as the field separator instead of the normal comma, and for each field, replaces newlines with spaces, and then prints out the transformed record.
In your specific case, you can also consider a workaround using GNU sed or awk.
An awk command will look like
awk 'NR==1 {print;next;} /^[0-9]{4,}\|/{print "\n" $0;next;}1' ORS="" file > newfile
The ORS (output record separator) is set to an empty string, which means that \n is only added before lines starting with four or more digits followed with a | char (matched with a ^[0-9]{4,}\| POSIX ERE pattern).
A GNU sed command will look like
sed -i ':a;$!{N;/\n[0-9]\{4,\}|/!{s/\n/ /;ba}};P;D' file
This reads two consecutive lines into the pattern space, and once the second line doesn't start with four digits followed with a | char (see the [0-9]\{4\}| POSIX BRE regex pattern), the or more line break between the two is replaced with a space. The search and replace repeats until no match or the end of file.
With perl, if the file is huge but it can still fit into memory, you can use a short
perl -0777 -pi -e 's/\R++(?!\d{4,}\|)/ /g' <<< "$s"
With -0777, you slurp the file and the \R++(?!\d{4,}\|) pattern matches any one or more line breaks (\R++) not followed with four or more digits followed with a | char. The ++ possessive quantifier is required to make (?!...) negative lookahead to disallow backtracking into line break matching pattern.
With your shown samples, this could be simply done in awk program. Written and tested in GNU awk, should work in any awk. This should work fast even on huge files(better than slurping whole file into memory, having mentioned that OP may use it on huge files).
awk 'gsub(/"/,"&")%2!=0{if(val==""){val=$0} else{print val $0;val=""};next} 1' Input_file
Explanation: Adding detailed explanation for above.
awk ' ##Starting awk program from here.
gsub(/"/,"&")%2!=0{ ##Checking condition if number of " are EVEN or not, because if they are NOT even then it means they are NOT closed properly.
if(val==""){ val=$0 } ##Checking condition if val is NULL then set val to current line.
else {print val $0;val=""} ##Else(if val NOT NULL) then print val current line and nullify val here.
next ##next will skip further statements from here.
}
1 ##In case number of " are EVEN in any line it will skip above condition(gusb one) and simply print the line.
' Input_file ##Mentioning Input_file name here.
My string is :
www.abc.texas.com
mail.texas.com
subdomain.xyz.cc.texas.com
www2.texas.com
I an trying to get results only with "one" word before texas.com. Expectation when I do a regex grep :
mail.texas.com
www2.texas.com
So mail & www2 are the "one" word that I'm talking about. I tried :
grep "*.texas.com", but I get all of them in results. Can someone please help ?
You can use
grep '^[^.]*\.texas\.com'
Details:
^ - start of string
[^.]* - zero or more chars other than a . char
\.texas\.com - .texas.com string (literal . char must be escaped in the regex pattern).
See the online demo:
#!/bin/bash
s='www.abc.texas.com
mail.texas.com
subdomain.xyz.cc.texas.com
www2.texas.com'
grep '^[^.]*\.texas\.com' <<< "$s"
Output:
mail.texas.com
www2.texas.com
With awk:
awk 'BEGIN{FS=OFS="."} /texas.com$/ && NF==3' file
Output:
mail.texas.com
www2.texas.com
Set one dot as input and output field separator, check for texas.com at the end ($) of your line and check for three fields.
See: 8 Powerful Awk Built-in Variables – FS, OFS, RS, ORS, NR, NF, FILENAME, FNR
With your shown samples, please try following awk code.
awk -F'.' 'NF==3 && $2=="texas" && $3=="com"' Input_file
Explanation: Simple making field separator as . for all the lines in awk program. Then in main program checking condition if NF==3(means number of fields in current line)are 3 AND 2nd field is texas and 3rd field is com if all 3 conditions are MET then print the line.
I have the next strings:
for example:
input1 = abc-def-ghi-jkl
input2 = mno-pqr-stu-vwy
I want extract the first word between "-"
for the fisrt string I want to get: def
if the input is the second string, I want to get: pqr
I want to use the command SED, Could you help me please?
Use
sed 's,^[^-]*-\([^-]*\).*,\1,' file
The string after the first - will be captured up to the second - and the rest will be matched, then the matched line will be replaced with the group text.
With bash:
var='input1 = abc-def-ghi-jkl'
var=${var#*-} # remove shortest prefix `*-`, this removes `input1 = abc-`
echo "${var%%-*}" # remove longest suffix `-*`, this removes `-ghi-jkl`
Or with awk:
awk -F'-' '{print $2}' <<<'input1 = abc-def-ghi-jkl'
Use - as input field separator and print the second field.
Or with cut:
cut -d'-' -f2 <<<'input1 = abc-def-ghi-jkl'
When you want to use sed, you can choose between solutions like
# Double processing
echo "$input1" | sed 's/[^-]*-//;s/-.*//'
# Normal approach
echo "$input1" | sed -r 's/^[^-]*-([^-]*)|-.*)/\1/g'
# Funny alternative
echo "$input1" | sed -r 's/(^[^-]*-|-.*)//g'
The obvious "external" tool would be cut. You can also look at a Bash builtin solution like
[[ ${input1} =~ ([^-]*)-([^-]*) ]] && printf %s "${BASH_REMATCH[2]}"
grep solution (in my opinion this is the most natural approach, as you are only trying to find matches to a regular expression - you are not looking to edit anything, so there should be no need for the more advanced command sed)
grep -oP '^[^-]*-\K[^-]*(?=-)' << EOF
> abc-qrs-bobo-the-clown
> 123-45-6789
> blah-blah-blah
> no dashes here
> mahi-mahi
> EOF
Output
qrs
45
blah
Explanation
Look at the inputs first, included here for completeness as a heredoc (more likely you would name your file as the last argument to grep.) The solution requires at least two dashes to be present in the string; in particular, for mahi-mahi it will find no match. If you want to find the second mahi as a match, you can remove the lookahead assertion at the end of the regular expression (see below).
The regular expression does this. First note the command options: -o to return only the matched substring, not the entire line; and -P to use Perl extensions. Then, the regular expression: start from the beginning of the line (^); look for zero or more non-dash characters followed by dash, and then (\K) discard this part of the required match from the substrings found to match the pattern. Then look for zero or more non-dash characters again - this will be returned by the command. Finally, require a dash following this pattern, but do not include it in the match. This is done with a lookahead (marked by (?= ... )).
I'm trying to automagically remove all lines from a text file that contains a letter "T" that is not immediately followed by a "H". I've been using grep and sending the output to another file, but I can't come up with the magic regex that will help me do this.
I don't mind using awk, sed, or some other linux tool if grep isn't the right tool to be using.
That should do it:
grep -v 'T[^H]'
-v : print lines not matching
[^H]: matches any character but H
You can do:
grep -v 'T[^H]' input
-v is the inverse match option of grep it does not list the lines that match the pattern.
The regex used is T[^H] which matches any lines that as a T followed by any character other than a H.
Read lines from file exclude EMPTY Lines and Lines starting with #
grep -v '^$\|^#' folderlist.txt
folderlist.txt
# This is list of folders
folder1/test
folder2
# This is comment
folder3
folder4/backup
folder5/backup
Results will be:
folder1/test
folder2
folder3
folder4/backup
folder5/backup
Adding 2 awk solutions to the mix here.
1st solution(simpler solution): With simple awk and any version of awk.
awk '!/T/ || /TH/' Input_file
Checking 2 conditions:
If a line doesn't contain T OR
If a line contains TH then:
If any of above condition is TRUE then print that line simply.
2nd solution(GNU awk specific): Using GNU awk using match function where mentioning regex (T)(.|$) and using match function's array creation capability.
awk '
!/T/{
print
next
}
match($0,/(T)(.|$)/,arr) && arr[1]=="T" && arr[2]=="H"
' Input_file
Explanation: firstly checking if a line doesn't have T then print that simply. Then using match function of awk to match T followed by any character OR end of the line. Since these are getting stored into 2 capturing groups so checking if array arr's 1st element is T and 2nd element is H then print that line.
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