How To Add Specific Word To First word in Fasta header
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6.5 years ago
empyrean999 ▴ 180

I have fasta file with different headers. Basically assembled fasta files some are assembled with different versions so they got same fasta names. When i tried to make a blast database with "-parse_seqids" its complaining me of duplicate id's. So i would like to add a extension to with version of assembly to its fasta headers. 

Examples 

Input fasta sequences : ( i am just showing headers here)

>Contig1_Node1_length20_cov30 Date:03/01/2015 Sequence_Organism:Other 

>Contig2_deg1 Date:03/01/2015 Sequence_Organism:Other 

>Contig3_jcg20839 Date:03/01/2015 Sequence_Organism:Other 

Output fasta sequences :

>Contig1_Node1_length20_cov30_V2 Date:03/01/2015 Sequence_Organism:Other 

>Contig2_deg1_V2 Date:03/01/2015 Sequence_Organism:Other 

>Contig3_jcg20839_V2 Date:03/01/2015 Sequence_Organism:Other 

 

perl awk sed unix • 2.0k views
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exclude the -parse_seqids" while creating blast database. It will not give any error.

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True but i need -parse_seqids to extract sequences from fasta file. 

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4
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6.5 years ago

Hi, here is a sed solution:

sed -e '/^>/ s/ /_V2 /' input.fa > output.fa

and a awk solution:

awk '{printf (/^>/) ? $1"_V2 "$2" "$3"\n" : $0"\n"}' input.fa > output.fa
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6.5 years ago
mxs ▴ 530

Ok, the simplest way is again either a perl of awk script:

perl -lne  'chomp;if(/>(.*?)\s+(.*)/){print ">$1_V2 $2"}else{print $_}' input.fa > output.fa

_V2   in the above line is what you are adding as an extension. If there are several different extensions then you should create a key table and preloaded as a hash table. Again everything can be done in a single line.

hope this helps

cheers

mxs

PS

please ask if anything is unclear regarding the above solution

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