Sentry Answers>Bash>

Delete all lines containing a string from a file in Bash

Delete all lines containing a string from a file in Bash

David Y.

—

The Problem

How can I delete all lines containing a particular string from a text file using Bash?

The Solution

We can do this using sed. For example, the following command will delete all lines containing the text “NOT FOR RELEASE” from the file info.txt:

Click to Copy
sed -i.bak '/NOT FOR RELEASE/d' ./info.txt

sed supports a large number of commands for editing text files. Here, we use the d command, which deletes lines. For example, 1d would delete the first line in the file, and 2d would delete the second line. If we provide a regular expression between /s instead of a line number, sed will delete every line that matches the expression.

The -i flag indicates that the change should be made in place. .bak is the suffix to use when creating a backup file. Before making any changes, sed will create a copy of info.txt in its original state called info.txt.bak. If we’re happy with the modified state of info.txt, we can delete this file. Otherwise, we can delete info.txt and rename info.txt.bak to info.txt to return to our initial state.

Remember that the text between /s is a regular expression, and will thus interpret certain characters as part of that syntax. If we merely want to search for a literal string, we will need to escape the characters $.*/[\]^ by preceding them with a backslash (\). For example:

Click to Copy
sed -i.bak '/NOT FOR RELEASE\./d' ./info.txt # will delete lines containing "NOT FOR RELEASE."

To learn more about sed, consult its manual page by typing man sed into your terminal.

  • Syntax.fmListen to the Syntax Podcast
  • ResourcesWhat is Distributed Tracing
  • Syntax.fm logo
    Listen to the Syntax Podcast

    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.

learn more about sentryjoin our discord
© 2025 • Sentry is a registered Trademark of Functional Software, Inc.