Regex to match string between quotes - regex

I'm using a shell script to read in a file and then piping the output to grep and trying to extract the string contained between two quotes (while excluding the quotes).
./readFile.sh | grep -e "[\^\"]*[\?\"]"
This returns the entire contents of the file I that I'm reading.
My file is organized this way:
TITLE="foo"
DATA="bar"
SERVER="foo.bar.server"
I read the regex tutorial here http://www.regular-expressions.info/lookaround.html and tried to use the lookahead and lookbehind as best as I could, but I don't understand what's wrong here.

check this example with grep with look-behind
kent$ echo 'TITLE="foo"
DATA="bar"
SERVER="foo.bar.server"'|grep -Po '(?<=")[^"]*'
foo
bar
foo.bar.server
alternative is grep -Po '"\K[^"]*'

If you want to give awk a chance it is pretty simple:
awk -F '"' 'NF>2{print $2}' inFile

I don't understand why you use a script for file reading, since grep works with files, but it's your own choice (maybe you do some preprocessing).
This extracts what is between '"':
$ grep -o '".*"' <file>
"foo"
"bar"
"foo.bar.server"
If you need to get rid of '"':
$ grep -o '".*"' <file> | tr -d '"'
foo
bar
foo.bar.server

If you want grep to return only the matching strings (and not the entire line) you should use the -o (or --only-matching) option.

Related

Extract few matching strings from matching lines in file using sed

I have a file with strings similar to this:
abcd u'current_count': u'2', u'total_count': u'3', u'order_id': u'90'
I have to find current_count and total_count for each line of file. I am trying below command but its not working. Please help.
grep current_count file | sed "s/.*\('current_count': u'\d+'\).*/\1/"
It is outputting the whole line but I want something like this:
'current_count': u'3', 'total_count': u'3'
It's printing the whole line because the pattern in the s command doesn't match, so no substitution happens.
sed regexes don't support \d for digits, or x+ for xx*. GNU sed has a -r option to enable extended-regex support so + will be a meta-character, but \d still doesn't work. GNU sed also allows \+ as a meta-character in basic regex mode, but that's not POSIX standard.
So anyway, this will work:
echo -e "foo\nabcd u'current_count': u'2', u'total_count': u'3', u'order_id': u'90'" |
sed -nr "s/.*('current_count': u'[0-9]+').*/\1/p"
# output: 'current_count': u'2'
Notice that I skip the grep by using sed -n s///p. I could also have used /current_count/ as an address:
sed -r -e '/current_count/!d' -e "s/.*('current_count': u'[0-9]+').*/\1/"
Or with just grep printing only the matching part of the pattern, instead of the whole line:
grep -E -o "'current_count': u'[[:digit:]]+'
(or egrep instead of grep -E). I forget if grep -o is POSIX-required behaviour.
For me this looks like some sort of serialized Python data. Basically I would try to find out the origin of that data and parse it properly.
However, while being hackish, sed can also being used here:
sed "s/.*current_count': [a-z]'\([0-9]\+\).*/\1/" input.txt
sed "s/.*total_count': [a-z]'\([0-9]\+\).*/\1/" input.txt

Grep and Egrep options

When I use grep -ow it affects the regex so I'm wondering what the regex would be without these options
I know that:
-o means show the line that matches the pattern
-w select lines that only match whole words
I'd like to convert egrep -ow '[1-9][0-9][0-9]+' text
egrep '[1-9][0-9][0-9]+' text but this regex is wrong with no options
You need to add word boundary.
egrep -o '\b[1-9][0-9][0-9]+\b' file
OR
Since egrep is depreciated, it's better to use grep with -E parameter.
grep -Eo '\b[1-9][0-9][0-9]+\b' file

Getting defined substring with help of sed or egrep

Everyone!!
I want to get specific substring from stdout of command.
stdout:
{"response":
{"id":"110200dev1","success":"true","token":"09ad7cc7da1db13334281b84f2a8fa54"},"success":"true"}
I need to get a hex string after token without quotation marks, the length of hex string is 32 letters.I suppose it can be done by sed or egrep. I don't want to use awk here. Because the stdout is being changed very often.
This is an alternate gnu-awk solution when grep -P isn't available:
awk -F: '{gsub(/"/, "")} NF==2&&$1=="token"{print $2}' RS='[{},]' <<< "$string"
09ad7cc7da1db13334281b84f2a8fa54
grep's nature is extracting things:
grep -Po '"token":"\K[^"]+'
-P option interprets the pattern as a Perl regular expression.
-o option shows only the matching part that matches the pattern.
\K throws away everything that it has matched up to that point.
Or an option using sed...
sed 's/.*"token":"\([^"]*\)".*/\1/'
With sed:
your-command | sed 's/.*"token":"\([^"]*\)".*/\1/'
YourStreamOrFile | sed -n 's/.*"token":"\([a-f0-9]\{32\}\)".*/\1/p'
doesn not return a full string if not corresponding

How can I extract the content between two brackets?

My input:
1:FAILED + *1 0 (8328832,AR,UNDECLARED)
This is what I expect:
8328832,AR,UNDECLARED
I am trying to find a general regular expression that allows to take any content between two brackets out.
My attempt is
grep -o '\[(.*?)\]' test.txt > output.txt
but it doesn't match anything.
Still using grep and regex
grep -oP '\(\K[^\)]+' file
\K means that use look around regex advanced feature. More precisely, it's a positive look-behind assertion, you can do it like this too :
grep -oP '(?<=\()[^\)]+' file
if you lack the -P option, you can do this with perl :
perl -lne '/\(\K[^\)]+/ and print $&' file
Another simpler approach using awk
awk -F'[()]' '{print $2}' file

Match two strings in one line with grep

I am trying to use grep to match lines that contain two different strings. I have tried the following but this matches lines that contain either string1 or string2 which not what I want.
grep 'string1\|string2' filename
So how do I match with grep only the lines that contain both strings?
You can use
grep 'string1' filename | grep 'string2'
Or
grep 'string1.*string2\|string2.*string1' filename
I think this is what you were looking for:
grep -E "string1|string2" filename
I think that answers like this:
grep 'string1.*string2\|string2.*string1' filename
only match the case where both are present, not one or the other or both.
To search for files containing all the words in any order anywhere:
grep -ril \'action\' | xargs grep -il \'model\' | xargs grep -il \'view_type\'
The first grep kicks off a recursive search (r), ignoring case (i) and listing (printing out) the name of the files that are matching (l) for one term ('action' with the single quotes) occurring anywhere in the file.
The subsequent greps search for the other terms, retaining case insensitivity and listing out the matching files.
The final list of files that you will get will the ones that contain these terms, in any order anywhere in the file.
If you have a grep with a -P option for a limited perl regex, you can use
grep -P '(?=.*string1)(?=.*string2)'
which has the advantage of working with overlapping strings. It's somewhat more straightforward using perl as grep, because you can specify the and logic more directly:
perl -ne 'print if /string1/ && /string2/'
Your method was almost good, only missing the -w
grep -w 'string1\|string2' filename
You could try something like this:
(pattern1.*pattern2|pattern2.*pattern1)
The | operator in a regular expression means or. That is to say either string1 or string2 will match. You could do:
grep 'string1' filename | grep 'string2'
which will pipe the results from the first command into the second grep. That should give you only lines that match both.
And as people suggested perl and python, and convoluted shell scripts, here a simple awk approach:
awk '/string1/ && /string2/' filename
Having looked at the comments to the accepted answer: no, this doesn't do multi-line; but then that's also not what the author of the question asked for.
Don't try to use grep for this, use awk instead. To match 2 regexps R1 and R2 in grep you'd think it would be:
grep 'R1.*R2|R2.*R1'
while in awk it'd be:
awk '/R1/ && /R2/'
but what if R2 overlaps with or is a subset of R1? That grep command simply would not work while the awk command would. Lets say you want to find lines that contain the and heat:
$ echo 'theatre' | grep 'the.*heat|heat.*the'
$ echo 'theatre' | awk '/the/ && /heat/'
theatre
You'd have to use 2 greps and a pipe for that:
$ echo 'theatre' | grep 'the' | grep 'heat'
theatre
and of course if you had actually required them to be separate you can always write in awk the same regexp as you used in grep and there are alternative awk solutions that don't involve repeating the regexps in every possible sequence.
Putting that aside, what if you wanted to extend your solution to match 3 regexps R1, R2, and R3. In grep that'd be one of these poor choices:
grep 'R1.*R2.*R3|R1.*R3.*R2|R2.*R1.*R3|R2.*R3.*R1|R3.*R1.*R2|R3.*R2.*R1' file
grep R1 file | grep R2 | grep R3
while in awk it'd be the concise, obvious, simple, efficient:
awk '/R1/ && /R2/ && /R3/'
Now, what if you actually wanted to match literal strings S1 and S2 instead of regexps R1 and R2? You simply can't do that in one call to grep, you have to either write code to escape all RE metachars before calling grep:
S1=$(sed 's/[^^]/[&]/g; s/\^/\\^/g' <<< 'R1')
S2=$(sed 's/[^^]/[&]/g; s/\^/\\^/g' <<< 'R2')
grep 'S1.*S2|S2.*S1'
or again use 2 greps and a pipe:
grep -F 'S1' file | grep -F 'S2'
which again are poor choices whereas with awk you simply use a string operator instead of regexp operator:
awk 'index($0,S1) && index($0.S2)'
Now, what if you wanted to match 2 regexps in a paragraph rather than a line? Can't be done in grep, trivial in awk:
awk -v RS='' '/R1/ && /R2/'
How about across a whole file? Again can't be done in grep and trivial in awk (this time I'm using GNU awk for multi-char RS for conciseness but it's not much more code in any awk or you can pick a control-char you know won't be in the input for the RS to do the same):
awk -v RS='^$' '/R1/ && /R2/'
So - if you want to find multiple regexps or strings in a line or paragraph or file then don't use grep, use awk.
git grep
Here is the syntax using git grep with multiple patterns:
git grep --all-match --no-index -l -e string1 -e string2 -e string3 file
You may also combine patterns with Boolean expressions such as --and, --or and --not.
Check man git-grep for help.
--all-match When giving multiple pattern expressions, this flag is specified to limit the match to files that have lines to match all of them.
--no-index Search files in the current directory that is not managed by Git.
-l/--files-with-matches/--name-only Show only the names of files.
-e The next parameter is the pattern. Default is to use basic regexp.
Other params to consider:
--threads Number of grep worker threads to use.
-q/--quiet/--silent Do not output matched lines; exit with status 0 when there is a match.
To change the pattern type, you may also use -G/--basic-regexp (default), -F/--fixed-strings, -E/--extended-regexp, -P/--perl-regexp, -f file, and other.
Related:
How to grep for two words existing on the same line?
Check if all of multiple strings or regexes exist in a file
How to run grep with multiple AND patterns? & Match all patterns from file at once
For OR operation, see:
How do I grep for multiple patterns with pattern having a pipe character?
Grep: how to add an “OR” condition?
Found lines that only starts with 6 spaces and finished with:
cat my_file.txt | grep
-e '^ .*(\.c$|\.cpp$|\.h$|\.log$|\.out$)' # .c or .cpp or .h or .log or .out
-e '^ .*[0-9]\{5,9\}$' # numers between 5 and 9 digist
> nolog.txt
Let's say we need to find count of multiple words in a file testfile.
There are two ways to go about it
1) Use grep command with regex matching pattern
grep -c '\<\(DOG\|CAT\)\>' testfile
2) Use egrep command
egrep -c 'DOG|CAT' testfile
With egrep you need not to worry about expression and just separate words by a pipe separator.
grep ‘string1\|string2’ FILENAME
GNU grep version 3.1
Place the strings you want to grep for into a file
echo who > find.txt
echo Roger >> find.txt
echo [44][0-9]{9,} >> find.txt
Then search using -f
grep -f find.txt BIG_FILE_TO_SEARCH.txt
grep '(string1.*string2 | string2.*string1)' filename
will get line with string1 and string2 in any order
for multiline match:
echo -e "test1\ntest2\ntest3" |tr -d '\n' |grep "test1.*test3"
or
echo -e "test1\ntest5\ntest3" >tst.txt
cat tst.txt |tr -d '\n' |grep "test1.*test3\|test3.*test1"
we just need to remove the newline character and it works!
You should have grep like this:
$ grep 'string1' file | grep 'string2'
I often run into the same problem as yours, and I just wrote a piece of script:
function m() { # m means 'multi pattern grep'
function _usage() {
echo "usage: COMMAND [-inH] -p<pattern1> -p<pattern2> <filename>"
echo "-i : ignore case"
echo "-n : show line number"
echo "-H : show filename"
echo "-h : show header"
echo "-p : specify pattern"
}
declare -a patterns
# it is important to declare OPTIND as local
local ignorecase_flag filename linum header_flag colon result OPTIND
while getopts "iHhnp:" opt; do
case $opt in
i)
ignorecase_flag=true ;;
H)
filename="FILENAME," ;;
n)
linum="NR," ;;
p)
patterns+=( "$OPTARG" ) ;;
h)
header_flag=true ;;
\?)
_usage
return ;;
esac
done
if [[ -n $filename || -n $linum ]]; then
colon="\":\","
fi
shift $(( $OPTIND - 1 ))
if [[ $ignorecase_flag == true ]]; then
for s in "${patterns[#]}"; do
result+=" && s~/${s,,}/"
done
result=${result# && }
result="{s=tolower(\$0)} $result"
else
for s in "${patterns[#]}"; do
result="$result && /$s/"
done
result=${result# && }
fi
result+=" { print "$filename$linum$colon"\$0 }"
if [[ ! -t 0 ]]; then # pipe case
cat - | awk "${result}"
else
for f in "$#"; do
[[ $header_flag == true ]] && echo "########## $f ##########"
awk "${result}" $f
done
fi
}
Usage:
echo "a b c" | m -p A
echo "a b c" | m -i -p A # a b c
You can put it in .bashrc if you like.
grep -i -w 'string1\|string2' filename
This works for exact word match and matching case insensitive words ,for that -i is used
When the both strings are in sequence then put a pattern in between on grep command:
$ grep -E "string1(?.*)string2" file
Example if the following lines are contained in a file named Dockerfile:
FROM python:3.8 as build-python
FROM python:3.8-slim
To get the line that contains the strings: FROM python and as build-python then use:
$ grep -E "FROM python:(?.*) as build-python" Dockerfile
Then the output will show only the line that contain both strings:
FROM python:3.8 as build-python
If git is initialized and added to the branch then it is better to use git grep because it is super fast and it will search inside the whole directory.
git grep 'string1.*string2.*string3'
searching for two String and highlight only string1 and string2
grep -E 'string1.*string2|string2.*string1' filename | grep -E 'string1|string2'
or
grep 'string1.*string2\|string2.*string1' filename | grep -E 'string1\|string2'
ripgrep
Here is the example using rg:
rg -N '(?P<p1>.*string1.*)(?P<p2>.*string2.*)' file.txt
It's one of the quickest grepping tools, since it's built on top of Rust's regex engine which uses finite automata, SIMD and aggressive literal optimizations to make searching very fast.
Use it, especially when you're working with a large data.
See also related feature request at GH-875.