How to prefix a specific series of lines (multiple)?

Question

I have a text file, which has an inconsistent timestamp format, that I would like to standardize. This is in a transcript from an interview; ultimately for textual analysis.

What command could I run 3x for each set of lines, through Linux terminal?

(1st) 00:0 before each line 1 thru 128 e.g. 0:32.6 becomes 00:00:32.6

(2nd) 00: before each line 129 thru 713 e.g. 10:02.6 becomes 00:10:02.6

(3rd) 0 before each line 714 thru 2285 e.g. 1:00:07.0 becomes 01:00:07.0

I'm aware I could split the file into 3, and add a different prefix to all of the lines of each file; but I need to execute numerous commands on the file, and constantly spliting and merging files would waste time.

The following articles:

https://unix.stackexchange.com/questions/336768/insert-character-in-the-beginning-of-specified-line-in-file

https://baeldung.com/linux/file-insert-prefix-every-line

I want to edit a specific lines (multiple) with sed command

Either handle only specific lines, or all lines; and I want to edit a specific series of lines

The best I could come up with:

$ sed "$(print -f '%ds/./00:0&/g;' 1 [thru] 128)" filename

But I don't know how the [thru] functionality would be included.

Barmar · Accepted Answer · 2025-10-09 16:41:39Z

3

You can use a range specification start,end before a command to restrict it to those line numbers. And you can use multiple -e options to execute different commands for different ranges.

sed -e '1,128s/^/00:0/' -e '129,713s/^/00:/' -e '714,2285s/^/0/' filename

There's no need to use the g option in your substitute commands, since ^ can only match once on a line.

answered Oct 9 at 16:41

Barmar

789k57 gold badges554 silver badges669 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Barmar Oct 10 at 14:20

You should accept the answer by clicking on the green checkmark.

Collectives™ on Stack Overflow

How to prefix a specific series of lines (multiple)?

1 Answer 1

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related