Delete Lines or Strings Between Two Patterns With Sed

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In this tutorial we will go through various ways to delete lines or strings between two patterns with the linux sed command stream editor.

For this tutorial we will use a plain text file named (file.txt) with the following contents:

PATTERN-1
- One
- one
- Two
- two
PATTERN-2
- one
- two
- One
- Two
PATTERN-3
- three

Notice that each word is repeated in both lower and uppercase.

Delete a Line Containing a Specific String Between Two Patterns

Delete the line containing the lowercase (one) between PATTERN-1 and PATTERN-2:

sed -i '/PATTERN-1/,/PATTERN-2/{/one/d}' file.txt

Delete the line containing the uppercase (One) between PATTERN-1 and PATTERN-2:

sed -i '/PATTERN-1/,/PATTERN-2/{/One/d}' file.txt

Delete the lines containing both lower and uppercase (O/one) between PATTERN-1 and PATTERN-2:

sed -i '/PATTERN-1/,/PATTERN-2/{/[oO]ne/d}' file.txt

Delete Line Number Ranges

If you know the line numbers you can delete them by range(from a line number to another).

Delete lines 4 to 9:

sed -i '4,9d' file.txt

Delete All Lines Between Two Patterns

Delete all the lines between PATTERN-2 and PATTERN-3:

sed -i '/PATTERN-2/,/PATTERN-3/{//!d}' file.txt

Delete all the lines between PATTERN-2 and PATTERN-3 including the patterns:

sed -i '/PATTERN-2/,/PATTERN-3/d' file.txt

Delete All Lines From a Pattern

Delete all lines from PATTERN-3 and on including the pattern:

sed -i '/PATTERN-3/,$d' file.txt

Delete all lines from PATTERN-3 not including the pattern:

sed -i '/PATTERN-3/,//{//!d}' file.txt

Conclusion

You should now be able to delete lines or strings between two patterns with sed. sed is a very powerful tool in the linux arsenal that you should be familiar and comfortable with.

For more sed commands, check out my other sed tutorial.

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