Regex to capture string until another string is encountered

Question

I want to match string1 and anything that appears in the following lines:

['string1','string2','string3']
['string1' , 'string2' , 'string3']
['string1.domain.com' , 'string2.domain.com' , 'string3.domain.com']
['string1.domain.com:8080' , 'string2.domain.com:8080' , 'string3.domain.com:8080']

Until it encounters the following:

string2

So with the right regex in the above 4 cases the results in bold would be matched:

['string1','string2','string3']

['string1' , 'string2' , 'string3']

['string1.domain.com' , 'string2.domain.com' , 'string3.domain.com']

['string1.domain.com:8080' , 'string2.domain.com:8080' , 'string3.domain.com:8080']

I tried using the following thread to solve my issue with https://regex101.com/

The regex I tried is from Question 8020848, but was not successful with matching the string correctly:

((^|\.lpdomain\.com:8080' , ')(string1))+$

But I was not successful in only matching the part I wanted to in this text:

['string1.domain.com:8080' , 'string2.domain.com:8080' , 'string3.domain.com:8080']

The following is what I received using the regex that you suggested

@@ -108,7 +108,7 @@ node stringA, stringB, stringC,stringD inherits default {
   'ssl_certificate_file' => 'test.domain.net_sha2_n.crt',
   'ssl_certificate_key_file'=> 'test.domain.net_sha2.key' }
 },
-    service_upstream_members         => ['string1.domain.com:8080', 'string2.domain.com:8080', 'string3.domain.com:8080', 'string4.domain.com:8080', 'string5.domain.com:8080'],
+    service_upstream_members         => [ 'string2.domain.com:8080', 'string3.domain.com:8080', 'string4.domain.com:8080', 'string5.domain.com:8080'],
 service2_upstream_members      => ['string9:8080','string10:8080'],
 service3_upstream_members  => ['string11.domain.com:8080','string12.domain.com:8080','string13.domain.com:8080'],
 service_name                      => 'test_web_nginx_z1',

As you can see, there is a preceding space that for some reason wasn't removed, even regex101.com demonstrates that all whitespaces are captured in the regex using

'string1[^']*'\s*,\s*

This is what I'm currently using (where server is a variable already defined in the script)

sed -i '' "s/'${server}[^']*'\s*,\s*//"

Good, but won't include spaces. There are several combinations that could be: ','string2 OR ' , 'string2 OR ', 'string2 need it to include everything up until the ' immediately before string2 — Wings
– Wings, Commented Nov 6, 2016 at 11:11
You mean you need spaces + comma + spaces, too? 'string1[^']*'\s*,\s*? — Wiktor Stribiżew
– Wiktor Stribiżew, Commented Nov 6, 2016 at 11:12
Try replacing both \s with [[:space:]]. Not sure it will help, I am no expert in Mac OSX, but yes, there is a difference as far as I know. — Wiktor Stribiżew
– Wiktor Stribiżew, Commented Nov 9, 2016 at 8:12

Wiktor Stribiżew · Accepted Answer · 2016-11-06 11:44:59Z

1

To match a string starting with ' then having string1, then any chars other than ', 0 or more occurrences, and then optional number of whitespaces, a comma and again 0+ whitespaces, you may use

'string1[^']*'\s*,\s*

See the regex demo.

Breakdown:

'string1 - a literal char sequence 'string1
[^']* - zero or more (*) characters other than ' (due to the negated character class [^...])
' - an apostrophe
\s* - 0+ whitespaces
, - a comma
\s* - 0+ whitespaces.

answered Nov 6, 2016 at 11:44

Wiktor Stribiżew

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Comments

tmslnz · Accepted Answer · 2016-11-06 11:57:01Z

1

This should match what you ask (according to your bold highlights) allowing for an unknown amount of spaces, etc.

(?:…) is a non-capturing group.
…+? is a non-greedy match (as few as possible of x)

~~(string1.+?)(?:'string2)~~

(string1.+?)'string2

See example: https://regex101.com/r/lFPSEM/3

edited Nov 6, 2016 at 11:57

answered Nov 6, 2016 at 11:36

tmslnz

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6 Comments

Wiktor Stribiżew Over a year ago

The (?:'string2) should not be inside a non-capturing group, there is only 1 branch inside the grouping construct here, and it is redundant.

tmslnz Over a year ago

You are right if you assume a consistent sequence of spaces, commas and single quotes is used. But your example would break as soon as that sequence is missing. I believe my approach reflects the OP's thinking of "from this until that" more closely.

Wiktor Stribiżew Over a year ago

If it is that, I'd close the question as a dupe of stackoverflow.com/questions/12736074/…, and the right pattern is ('string1.+?)'string2

tmslnz Over a year ago

Yup. A redundant non-capturing group :)

Wiktor Stribiżew Over a year ago

The (string1.+?)'string2 will capture "string1', 'string0.sssss', " in ['string1', 'string0.sssss', 'string2','string3'] and I doubt it is what is required judging by the provided input.

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