Aloha,
I am having trouble figuring out how to remove everything after the last '_' in the sequence headers of a fasta file.
I would like this following series of headers
>ART01B_100_M7_ID100005_1
TAAGAGGAGGAATTTTTCATAGAGGATTGTCTGTAGACTTAGTAATTTTTTCTCTTCATTTAGCTGGAATTTCTTCTCTT
TTAGGGGCTGTAAATTTTATTACTACAATTCTTAATTGTCGATCTTTAGGGGTTTGGTGAGATGAATTGCCCTTATTTGT
>PAG05A_100_M7_ID102325_189
TAAGAGGAGGAATTTTTCATAGAGGATTGTCTGTAGACTTAGTAATTTTTTCTCTTCATTTAGCTGGAATTTCTTCTCTT
TTAGGGGCTGTAAATTTTATTACTACAATTCTTAATTGTCGATCTTTAGGGGTTTGGTGAGATGAATTGCCCTTATTTGT
>KIN05B_100_M7_ALT_ID230005_46
TAAGAGGAGGAATTTTTCATAGAGGATTGTCTGTAGACTTAGTAATTTTTTCTCTTCATTTAGCTGGAATTTCTTCTCTT
TTAGGGGCTGTAAATTTTATTACTACAATTCTTAATTGTCGATCTTTAGGGGTTTGGTGAGATGAATTGCCCTTATTTGT
to look like this:
>ART01B_100_M7_ID100005
TAAGAGGAGGAATTTTTCATAGAGGATTGTCTGTAGACTTAGTAATTTTTTCTCTTCATTTAGCTGGAATTTCTTCTCTT
TTAGGGGCTGTAAATTTTATTACTACAATTCTTAATTGTCGATCTTTAGGGGTTTGGTGAGATGAATTGCCCTTATTTGT
>PAG05A_100_M7_ID102325
TAAGAGGAGGAATTTTTCATAGAGGATTGTCTGTAGACTTAGTAATTTTTTCTCTTCATTTAGCTGGAATTTCTTCTCTT
TTAGGGGCTGTAAATTTTATTACTACAATTCTTAATTGTCGATCTTTAGGGGTTTGGTGAGATGAATTGCCCTTATTTGT
>KIN05B_100_M7_ALT_ID230005
TAAGAGGAGGAATTTTTCATAGAGGATTGTCTGTAGACTTAGTAATTTTTTCTCTTCATTTAGCTGGAATTTCTTCTCTT
TTAGGGGCTGTAAATTTTATTACTACAATTCTTAATTGTCGATCTTTAGGGGTTTGGTGAGATGAATTGCCCTTATTTGT
because there are various '_' in the sequence headers, this command, for example, won't work:
cat Alt_MACSE_Output.fasta | awk -F _ '/^>/ { print $1"_"$2"_"$3"_"$4 } /^[A-Z]/ {print $1}' > Alt.fasta
Can anyone help me please?
4 answers
You can do this with sed
$ sed 's/_[^_]*$//' input.fa > output.fa
fin swimmer
Sure,
BEGIN{OFS=FS="_"} Before anything is read, underscore is set as field separator (FS) and output field separator (OFS). If OFS was omitted it would default to space and we would have >ART01B 100 M7 ID100005 instead of >ART01B_100_M7_ID100005
{if(/^>/){NF--}} If a line begins with ">" (e.g. it's a header line in fasta format), number of fields (NF) is reduced by one. NF = Number of fields, $NF = the value in the last field. The value in the second last field would be referred to as $(NF-1). Thus NF-- reduces number of fields by one (it could also be NF-=1). $NF-- would reduce the value in the last field by one, e.g. 3 would become 2. I think any non-numerical would become -1 because the operation was false..
{print $0} Print the whole line, you could replace this with just "1", but IMO it's more clear to always write it like this..
Another sed solution:
$ sed '/>/ s/\(.*\)_.*$/\1/g' test.fa
>ART01B_100_M7_ID100005
TAAGAGGAGGAATTTTTCATAGAGGATTGTCTGTAGACTTAGTAATTTTTTCTCTTCATTTAGCTGGAATTTCTTCTCTT
TTAGGGGCTGTAAATTTTATTACTACAATTCTTAATTGTCGATCTTTAGGGGTTTGGTGAGATGAATTGCCCTTATTTGT
>PAG05A_100_M7_ID102325
TAAGAGGAGGAATTTTTCATAGAGGATTGTCTGTAGACTTAGTAATTTTTTCTCTTCATTTAGCTGGAATTTCTTCTCTT
TTAGGGGCTGTAAATTTTATTACTACAATTCTTAATTGTCGATCTTTAGGGGTTTGGTGAGATGAATTGCCCTTATTTGT
>KIN05B_100_M7_ALT_ID230005
TAAGAGGAGGAATTTTTCATAGAGGATTGTCTGTAGACTTAGTAATTTTTTCTCTTCATTTAGCTGGAATTTCTTCTCTT
TTAGGGGCTGTAAATTTTATTACTACAATTCTTAATTGTCGATCTTTAGGGGTTTGGTGAGATGAATTGCCCTTATTTGT
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