Add a new column with Line number to a pipe delimited file

Question

I am really struggling to add a new column with the line number in the terminal to a pipe delimited file

My current file looks like this:

ID|FirstName|LastName
12|John|Svernson
23|Mark|Wright
11|Chris|Watson

And I want the file to look like the following:

LN|ID|FirstName|LastName
1|12|John|Svernson
2|23|Mark|Wright
3|11|Chris|Watson

I have over 90k lines. I couldn't find a way to do this. Any help or guidance would be appreciated. Thanks

Strip the header and pipe the data to `nl -ba -s\|` – William Pursell Oct 12 '18 at 15:19 — William Pursell, Oct 12 '18 at 15:19

score 4 · Answer 1 · answered Oct 12 '18 at 15:39

4

A fun alternative:

{ echo LN; seq $(( $(wc -l < file) - 1 )); } | paste -d'|' - file

although in reality I'd use

awk '{print (NR==1 ? "LN" : NR-1), $0}' OFS="|" file

answered Oct 12 '18 at 15:39

glenn jackman

RavinderSingh13 · Accepted Answer · 2018-10-12T15:26:34.510

2

could you please try following.

awk 'FNR==1{print "LN|"$0;next} {$1=++count "|" $1} 1'   Input_file

To write output into Input_file itself append > temp_file && mv temp_file Input_file in above code too.

edited Oct 12 '18 at 15:26

answered Oct 12 '18 at 15:02

RavinderSingh13

@Nant, please see my update for saving output into Input_file itself one. – RavinderSingh13 Oct 12 '18 at 15:20
1

You need to do smth with the header because it becomes wrong and shifted – Corentin Limier Oct 12 '18 at 15:25
@CorentinLimier, cool thanks for letting me know edited it now(along with saving output into Input_file too). – RavinderSingh13 Oct 12 '18 at 15:27
@RavinderSingh13 this is exactly what I was looking for. Thanks – Nant Oct 15 '18 at 13:26

score 1 · Answer 3 · answered Oct 12 '18 at 15:01

1

Use awk variable NR (record number):

awk -F'|' 'NR==1{print "LN" FS $0}NR!=1{print NR-1 FS $0}' file

answered Oct 12 '18 at 15:01

Corentin Limier

thanks for this but this doesn't actually write this in the file right? It's just prints it out? Is there a way to save this in the file? – Nant Oct 12 '18 at 15:18
1

@Nant https://stackoverflow.com/questions/16529716/awk-save-modifications-in-place – Corentin Limier Oct 12 '18 at 15:19

score 0 · Answer 4 · answered Oct 12 '18 at 15:32

0

I would use nl. You may run into issues if your line number goes over 6 digits, but you can add a -w to increase the number width if you need to:

   { read line; echo "LN|$line"; cat | nl -w 10 -ba -s \|; } < input | 
       sed 's/^ *//';

answered Oct 12 '18 at 15:32

William Pursell

4 Answers4