Write a regular expression to match lines not containing a word
David Y.
—The Problem
How can I write a regular expression to match lines not containing a specific word?
The Solution
You can do this using a negative lookahead assertion. The PCRE regular expression below will match any line that does not contain the word “word”:
/^((?!word).)*$/gm
Here’s what it does:
/: Start regular expression.^: Match the beginning of a line.(: Start capture group 1.(?!word): Negative lookahead assertion. If “word” is found, discard the current match, otherwise continue evaluating the expression..: Match any character.): End capture group 1.*: Match 0 or more of capture group 1.$: Match the end of the line./: End regular expressiong: Global flag. Find all matches in the string, not just the first one.m: Multiline flag. Use^and$to match the start and end of a line, rather than the start and end of the whole string.
Notably, this expression will not match empty lines. If this behavior is desired, we can add the s (dotall) flag, which will make . match all characters including newlines:
/^((?!word).)*$/gms
If the s flag is not supported by your regex implementation, you can replace . with [\s\S] (\s matches whitespace characters, and \S matches everything except whitespace characters).
/^((?!word)[\s\S])*$/gm
- Syntax.fmListen to the Syntax Podcast
- ResourcesWhat is Distributed Tracing
- Listen to the Syntax Podcast
![Syntax.fm logo]()
Tasty treats for web developers brought to you by Sentry. Get tips and tricks from Wes Bos and Scott Tolinski.
SEE EPISODES
Considered “not bad” by 4 million developers and more than 100,000 organizations worldwide, Sentry provides code-level observability to many of the world’s best-known companies like Disney, Peloton, Cloudflare, Eventbrite, Slack, Supercell, and Rockstar Games. Each month we process billions of exceptions from the most popular products on the internet.
A peek at your privacy
Here’s a quick look at how Sentry handles your personal information (PII).
×Who we collect PII from
We collect PII about people browsing our website, users of the Sentry service, prospective customers, and people who otherwise interact with us.
What if my PII is included in data sent to Sentry by a Sentry customer (e.g., someone using Sentry to monitor their app)? In this case you have to contact the Sentry customer (e.g., the maker of the app). We do not control the data that is sent to us through the Sentry service for the purposes of application monitoring.
Am I included?PII we may collect about you
- PII provided by you and related to your
- Account, profile, and login
- Requests and inquiries
- Purchases
- PII collected from your device and usage
- PII collected from third parties (e.g., social media)
How we use your PII
- To operate our site and service
- To protect and improve our site and service
- To provide customer care and support
- To communicate with you
- For other purposes (that we inform you of at collection)
Third parties who receive your PII
We may disclose your PII to the following type of recipients:
- Subsidiaries and other affiliates
- Service providers
- Partners (go-to-market, analytics)
- Third-party platforms (when you connect them to our service)
- Governmental authorities (where necessary)
- An actual or potential buyer
We use cookies (but not for advertising)
- We do not use advertising or targeting cookies
- We use necessary cookies to run and improve our site and service
- You can disable cookies but this can impact your use or access to certain parts of our site and service
Know your rights
You may have the following rights related to your PII:
- Access, correct, and update
- Object to or restrict processing
- Port over
- Opt-out of marketing
- Be forgotten by Sentry
- Withdraw your consent
- Complain about us
If you have any questions or concerns about your privacy at Sentry, please email us at compliance@sentry.io.
If you are a California resident, see our Supplemental notice.