How can I display 3 lines of text at a time onto 1 line?

Question

I have a log file that displays data 3 lines at a time. Like this:

1 data 2 data 3 data 1 data 2 data 3 data 1 data 2 data 3 data

I'd like to take each 3 lines and display them on 1 line like this:

1 data 2 data 3 data 1 data 2 data 3 data 1 data 2 data 3 data

I'd like to be able to cat this file and then pipe it through a command(s) that will do this for me. I suspect sed or awk are a solution.

Runium · Accepted Answer · 2016-02-26 19:53:51Z

10

You might be able to use paste:

$ paste - - - <data.txt 1 data 2 data 3 data 1 data 2 data 3 data 1 data 2 data 3 data

answered Feb 26, 2016 at 19:53

30.1k5 gold badges57 silver badges77 bronze badges

terdon · Accepted Answer · 2016-02-26 19:47:40Z

Here's one way:

$ perl -pe 's/\n/ / unless $. % 3 == 0' file 1 data 2 data 3 data 1 data 2 data 3 data 1 data 2 data 3 data

thrig · Accepted Answer · 2016-02-26 21:42:51Z

2

Or also sed by "N"omming two lines and then nixing the newlines in the resulting buffer.

sed 'N;N;s/\n/ /g'

answered Feb 26, 2016 at 21:42

35.8k4 gold badges70 silver badges88 bronze badges

3 Answers 3