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UNIX for Beginners Q & A
1

Hi,

I wonder what does :

 export pubkey=$(cat ~/.ssh/id_rsa.pub)

print "from=\"$host_ad\",something $pubkey"

Thanks for explanation.

2

If that text is sitting in a file that is never executed, it just sits there.

If it is in a file that is executed by a shell, it depends on what shell is being used to interpret that file.

What file is it in? What operating system are you using? What shell is being used to interpret this file?

Is there a definition for the variable host_ad in this file before the lines you have shown us? If not, is there a definition for that variable exported in the environment of the process that invokes the file that contains this text?

3

Hi,
Thank you.
What file is it in? A script that will be executed to verify or configure ssh connection.
What operating system are you using? Linux redhat or Unix AIX.
What shell is being used to interpret this file? ksh.

Is there a definition for the variable host_ad in this file before the lines you have shown us? No. But seems to be an ip address.
is there a definition for that variable exported in the environment of the process that invokes the file that contains this text? As I can see it is the content of id_rsa.pub which is a SSL certificat.
Thanks and regards.

4

ksh comes in (at least) two versions, and the two OSes you mentioned seem to used different ones as their default. Having said this, man ksh usually helps. see below quotations.

So - a variable called pubkey is - by "command substitution" - assigned the stdout of a cat command and marked for export.

So - you'll have something like

from="",no-port-forwarding ssh-rsa AAAA...

on your stdout, usually your screen.

5

Thanks.