Question

I found this call in an app I started managing some time ago:

/usr/bin/sftp -b – -o Port=22 abc12@90.00.00.44

Whats suspicious is -b – -o … isnt it? I think the param is missing here…

Thanks

Answer 1

I don’t believe there’s anything suspicious about it.

The -b - is simply reading the script from standard input which we can’t tell from your sample where it’s coming from. It may be redirected or it may just interact with the user. The - file name is quite prevalent at meaning standard input. Try cat - under Linux for example.

The sftp manpage states this clearly:

A batchfile of '-' may be used to indicate standard input.

The -o Port=22 is simply setting the SSH option to use port 22 (which is usually the default anyway).