Read first x lines of csv file into new outfile?

csv, shell, terminal

Solution

Brief

(You'll use a linux terminal/console)

Use `head -n NUMBEROFLINES file.csv` to get the first `NUMBEROFLINES` of lines. Write it into another file using shell redirection (`>`) like this:

head -n NUMBEROFLINES file.csv > mynewfile.csv

Note that this will totally recreate `mynewfile.csv`, if it had any content before it is now deleted forever(-ish).

If you ever happen to want the opposite (last x lines), use `tail`.

Both tools come with man and info pages (`man head` or `info head` - get used to `man`, though) and a `--help` flag (`head --help` actually shows me more or less the man page).

Full example

head -n 10 data.csv >> /tmp/first_and_last.csv # Note the ">>"
tail -n 10 data.csv >> /tmp/first_and_last.csv # Note the ">>"

This would open the file `/tmp/first_and_last.csv` and attach (`>>`, `>` would recreate/delete the file!) the first and the last 10 lines of `data.csv` at the "end" of `/tmp/first_and_last.csv`.

Mac OS X: According to the internet (tm) these commands are available in (Unix-based) Mac OS as well (you have to start the Terminal via Finder).

More speaking examples

`-n` is short for `--lines=`, so you could also use:

tail --lines=10 data.csv >> addtothisfile.txt
head --lines=10 data.csv >> addtothisfile.txt

Problem

Original source