add string in each line at the begining of column

Question

I am interested in adding a string chr to the beginning of column in each line.

The file is tab delimited and looks something like:

re1 1   AGT
re2 1   AGT
re3 2   ACGTCA
re12    3   ACGTACT

what I need is:

re1 chr1    AGT
re2 chr1    AGT
re3 chr2    ACGTCA
re12    chr3    ACGTACT

The solution can be a bash one-liner

score 16 · Accepted Answer · answered Aug 05 '13 at 15:20

What about this?

$ awk '$2="chr"$2' file
re1 chr1 AGT
re2 chr1 AGT
re3 chr2 ACGTCA
re12 chr3 ACGTACT

Explanation

With $2="chr"$2 we add chr to the 2nd field. Then we do not need any other command to get the desired output, as the default behaviour of awk is print $0.

To make sure the OFS (output field separator) is a tab, you can do the following:

$ awk 'BEGIN{OFS="\t"}$2="chr"$2' file
re1     chr1    AGT
re2     chr1    AGT
re3     chr2    ACGTCA
re12    chr3    ACGTACT

Good that it worked to you, @Irek! Remember you can mark one of the answers as accepted if your issue is already solved. Greetings — fedorqui, Aug 05 '13 at 15:30

score 4 · Answer 2 · answered Aug 05 '13 at 15:20

4

Awk one-liner do?

$ awk -v OFS=$'\t' '{ $2="chr" $2; print}' so.txt
re1     chr1    AGT
re2     chr1    AGT
re3     chr2    ACGTCA
re12    chr3    ACGTACT

answered Aug 05 '13 at 15:20

MattH

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How would you do this for EVERY column after the first column. Would the code change if the number of columns varies for each row? – Sky Scraper Mar 07 '21 at 18:08

score 1 · Answer 3 · answered Aug 05 '13 at 15:21

1

sed one-liner:

sed 's/\<[0-9]\>/chr&/' < input > output

answered Aug 05 '13 at 15:21

mohit

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add string in each line at the begining of column

3 Answers3

Explanation

Linked