Extract fasta-headers that have the same word

Question

[genomes_and_MGEs]

Hey guys,

I have a multi-fasta protein file like this

>SF_hydrolase MKG...
>LH_reductase MKI...
>SM_hydrolase MSN...

Basically, I would like to extract only the fasta headers that have the other "reductase". I know how to extract headers that have the same headers as the ones present on a list, but I don't know how to extract fasta-headers solely based on one of the words.. Hope you can help me! Cheers

Answer 1

[GenoMax]

grep is your friend. It will look for words you specify in lines.

[Kevin Blighe]

...and you can use grep -A and grep -B to extract lines before or after the line on which the matching keyword was found.

[harish]

That's a valid option, but sometimes fasta sequences might be wrapped in which case it might be a bit difficult. Why not use grep and parse it using a fasta parser?