How to delete lines in file from specific position to the end of the file

Question

I have a file with many lines.

I want to delete from the line 1458 to the end of the file. I think that I can do it with sed, but I do not know how to.

score 19 · Accepted Answer · answered Jul 05 '16 at 23:36

19

sed '1458,$d'

You can use that with -i to edit the file in place if necessary.

e.g

sed -i '1458,$d' filename.txt

answered Jul 05 '16 at 23:36

Stephen Harris

44,540

1

Excellent! Here is another example. printf 'apple\nbanana\nbanana: celery\n\ndates,fish,grapes\n' | sed '/banana:/,$d' – Victoria Stuart Apr 30 '19 at 16:32

score 5 · Answer 2 · edited Jul 06 '16 at 00:00

5

There are many possibilities to do that, but if the file is very big it is better to stop processing any lines after given position and just quit. This is exactly what the command q is designed for in sed:

sed 1458q file

edited Jul 06 '16 at 00:00

Jeff Schaller

67,283
35
116
255

answered Jul 05 '16 at 23:53

jimmij

47,140

score 2 · Answer 3 · answered Jul 05 '16 at 23:43

$ head -n 1458 myfile > myfile.tmp ; mv myfile.tmp myfile

Side note: To my knowledge, there's no clear way to shorten a file (in bash/shell etc) based on number of lines, that doesn't involve creating a new file first (which is what sed, or sed -i(n place) does.) This matters if remaining disk space is insufficient to accommodate the newly written file. In that case, if you can roughly guess as to the size of the new file, truncate -s {number of bytes} myfile does lop the end of the file off, without creating a new one.

Interesting read: http://unix.stackexchange.com/a/186126/117549 — Jeff Schaller, Jul 06 '16 at 00:02

How to delete lines in file from specific position to the end of the file

3 Answers3