Repeat each line in a text n times

Question

I have a file that looks like this

888
924
873
1374
.....

The dots indicate that I have many more string, around 3000. I want repeat each string n time, to have something like this;

888
888
888
924
924
924
873
873
873
....

I tried to write a small bash code:

#! bin/bash

while IFS= read -r line

do 
    awk 'NR==line'
    awk 'NR==line'
    awk 'NR==line'
done < /<PATH_TO_FILE>

But I get no results. I thought that this was a quite easy task, but obviously I am missing something. Any advise?

Solution 1

It can easily be done in perl:

perl -ne 'print $_ x 3' file

the above oneliner output:

$ perl -ne 'print $_ x 3' file
888
888
888
924
924
924
873
873
873
1374
1374
1374

Just change the sample value for your needs.

An awk solution:

awk '{for (i = 1; i <= 3; i++) print $1}' file

To fix your bash script I would use the following snippet instead:

#!/bin/bash

while read line
do
    for i in {1..3}; do echo $line; done
done < ./file

Solution 2

There is a nice trick to print a string repeatedly:

$ printf "%0.s-" {1..10}
----------

Based on that, we can loop through the file and print the line as many times as we indicate in the brace expression:

while IFS= read -r line
do
printf "%0.s$line\n" {1..3}
done < file

Test

                          change this number as you wish
                                                       v
$ while IFS= read -r line; do printf "%0.s$line\n" {1..3}; done < a
888
888
888
924
924
924
873
873
873
1374
1374
1374

Although my preference would be to use an awk like this, very similar to what others posted before (nice answers by the way):

awk -v tot=3 '{for (i=1; i<=tot; i++) print}' file

Solution 3

You could simply do this through sed.

$ sed 's/\(.*\)/\1\n\1\n\1/g' file
888
888
888
924
924
924
873
873
873
1374
1374
1374

Comments

[choroba]

perl -ne 'print $_ x 3' file is even easier.

[Sylvain Pineau]

@choroba: indeed, I tried but forgot that it required spaces around the x operator. Thanks. I'm updating the answer.

[efrem]

great thanks. I would prefer an awk solution, because I know it a bit better and I have to edit the file even more after performing this first step.

[Sylvain Pineau]

@efrem: I've updated my answer with an awk solution

[efrem]

works perfectly, any idea why my code sucked?

[Sylvain Pineau]

@efrem: It seems that the awk commands were unneeded. See my update