Use of cutomized blastn datagase

[e.tortoli]

I have installed ncbi-blast-2.3.0 in my PC
I have created a custom database (I think it is made of the 6 new files named after my database name with different extensions: .nhr .nin .nog .nds .nsi nsq)
To interrogate this database with the sequence file abc.fsa, while within the directory containing the 6 files above I input:
blastn -db custom_database_name -query abc.fsa
I get the following message: Too many positional arguments (1), the offending value: -db
What did I make wrong?
Thanks in advance.

Enrico

[GenoMax]

Are you using just the "basename" of the blast index as an argument for -db? Your query and database are both nucleotide sequences?

[maubp]

Did you copy and paste the command, or type it directly? It should be a minus sign then db, but if you copied it from a PDF you can get a long dash symbol which looks like a minus sign but isn't. That would explain the error message.

[GenoMax]

Good catch Peter. Smart hyphens (and related "smart" things) can cause unintended consequences on copy/paste. This is the most likely explanation here.

[e.tortoli]

Are you using just the "basename" of the blast index as an argument for -db? Your query and database are both nucleotide sequences?

Thanks for your reply,
yes the name of my database is MYCdb and I use such name as an argument of -db
Both query and database are nucleotide sequences

[GenoMax]

Did you look into @Peter's (maubp) suggestion or does that not apply?

[e.tortoli]

I tried again just now paying attention to use the minus;.
Now I have a different error message: Unknown argument: title
Actually typing
blastn -help
I do not see -title in the help-list
Thanks everibody
Enrico

[e.tortoli]

It works now, I was using -title instead of -db.
Thanks everybody, sorry for my foolishness.

Enrico