[SOLVED] Replacing special character by new line

Issue

I have following lines in a text file. I would like to remove last '_' and add a new line character after that.

>15_48499991_ENSG00000074803_C_G_G_CCAATCGCTTTCAAGTTAGTGTG
>15_48499991_ENSG00000074803_C_G_G_CAATCGCTTTCAAGTTAGTGTGA
>15_48499991_ENSG00000074803_C_G_G_AATCGCTTTCAAGTTAGTGTGAT

Desired output:

>15_48499991_ENSG00000074803_C_G_G
CCAATCGCTTTCAAGTTAGTGTG
>15_48499991_ENSG00000074803_C_G_G
CAATCGCTTTCAAGTTAGTGTGA
>15_48499991_ENSG00000074803_C_G_G
AATCGCTTTCAAGTTAGTGTGAT

I have used below SED query to perform this operation. I am not able to figure out the problem in my query.

sed 's/\_/'\n'/g'

Solution

You can have .* eat as much of the line as it can (because * is greedy) before matching _,

sed 's/\(.*\)_/\1\n/' file

or the debatably nicer

sed -E 's/(.*)_/\1\n/' file

Concerning your attempt, it has 3 errors:

• _ needs not be escaped
• ' cannot be nested (this is because of the shell, not of sed); fwiw, I don't understand why you've put them there: what were you trying to do?
• if you fix the two above, ending up with sed 's/_/\n/g', you would be substituting all _s, rather than only the last one.

Answered By - Enlico

Answer Checked By - Marie Seifert (WPSolving Admin)