I have two files, `A.tsv` and `B.tsv`:

A.tsv (field separator = `\t`):

```
Sample ID   Internal Control    Result  Consensus   
4686427 Pass    Not Detected    Not Available
4666275 Pass    Detected    Not Available
4666295 Pass    Detected    Available
4644444 Pass    Detected    Available

```

B.tsv (field separator = `\t`):

```
seqName clade   substitutions   deletions
4666295 A8A yes no
4666275 18A no  yes
4686427 161 no  yes

```

And I want to combine those two file into a new file like this :

```
Sample ID   Internal Control    Result  Consensus   clade   substitutions   deletions   
4686427 Pass    Not Detected    Not Available   161 no  yes
4666275 Pass    Detected    Not Available   18A no  yes
4666295 Pass    Detected    Available   A8A yes no
4644444 Pass    Detected    Available

```

I've write this but it does not print the header and print also the first line of the second file :

```
awk -F '\t' -v OFS="\t" 'NR==FNR{a[$1]=$0;next}{print $0,a[$1]}' B.tsv A.tsv > C.tsv

```

So how to do it properly ? Thanks

PS: I've subsample the file, the real one are bigger in term of line and column