Find Long Lines With awk

When working with code or text files, you may need to find lines that exceed a certain character limit, especially when following coding standards that enforce line length limits.

You can use awk to find lines longer than a specific number of characters. For example, the following command shows you the line numbers and character counts for any lines longer than 80 characters in the file app.js:

awk 'length > 80 {print NR": "length" chars"}' app.js

You’ll receive output that looks like the following:

15: 85 chars
23: 92 chars
47: 106 chars

Here’s how it works:

• length: awk’s built-in function that returns the length of the current line
• > 80: The condition that checks if the line length exceeds 80 characters
• {print NR": "length" chars"}: The action to perform when the condition is true:
  • NR is awk’s built-in variable for the current line number
  • length shows the actual character count
  • The output format shows both line number and character count

You can adjust the character limit by changing the number:

awk 'length > 120 {print NR": "length" chars"}' filename.py

To see the actual content of long lines, include the line text by using #0:

awk 'length > 80 {print NR": "length" chars - "$0}' filename.js

This is useful for identifying lines that you’ll need to reformat to meet coding standards or readability guidelines.