How do I truncate a csv file?

Question

I have a csv file that is 6 gigabytes, but I don't need that much data, I need like 100 rows or so. How can I truncate it?

@K7AAY, sorry, I have no idea, that would require me to download the whole thing from s3 and check, which will take a while. — Pavel Orekhov, May 29 '19 at 15:40
@K7AAY do csv files have '\n' at the end, should i just readline 100 times and write it to another file? — Pavel Orekhov, May 29 '19 at 15:42
Windows and DOS use carriage return and line feed ("\r\n") as a line ending, which Unix uses just line feed ("\n"). — K7AAY, May 29 '19 at 15:44

terdon · Accepted Answer · 2019-05-29T17:51:11.767

8

Depending on what you want you can:

Take the 1st 100 rows as suggested by @K7AAY.
```
head -n100 filename.csv > file100.csv  
```

Take the last 100 rows

tail -n100 filename.csv > file100.csv

edited May 29 '19 at 17:51

answered May 29 '19 at 15:58

terdon

What if one of the fields can contain newlines? – Big McLargeHuge Oct 14 '20 at 22:13
@BigMcLargeHuge then you use a dedicated csv parser. – terdon Oct 14 '20 at 22:54

K7AAY · Answer 2 · 2019-05-29T16:04:03.250

2

Use head to display only the first 100 lines and direct them to a new file. Please substitute the current file name for filename.csv:

head -n100 filename.csv > file100.csv

edited May 29 '19 at 16:04

answered May 29 '19 at 15:43

K7AAY

2 Answers2