How do I run a command on lines near each match, not just the matching line itself?

Explanation

The :g (global) command normally operates on lines that match a pattern. But you can use range offsets to target lines around each match instead. This is powerful for deleting, joining, or modifying context lines surrounding a pattern.

How it works

• :g/pattern/ — finds every line matching pattern
• .-1,.+1 — creates a range from 1 line above (.−1) to 1 line below (.+1) relative to the matched line
• d — deletes that entire 3-line range

The . in the range refers to the current matched line. You can use any offset: .-2,.+3 targets 2 lines above through 3 lines below.

Example

Given this log file:

timestamp: 10:00
DEBUG: entering function
timestamp: 10:01
ERROR: null pointer
timestamp: 10:02
DEBUG: exiting function

Running :g/DEBUG/.-1,.+1d removes each DEBUG line along with the timestamp above and below it, leaving only the ERROR block.

Tips

• Use :g/pattern/.+1d to delete only the line after each match
• Combine with join instead of d: :g/pattern/.,. +1join merges each match with the next line
• The offsets are processed top-to-bottom, so overlapping ranges may cause unexpected behavior — use :g/pattern/.-1,.+1d on non-adjacent matches for best results
• Use :g/pattern/.,$d to delete from each match to the end of the file (stops at first match)