I am trying to convert the following two lines of a bash script
to perl.

#start gnetcat on backup server
gnetcat -l -vv -p 2011 >$STORAGE_FILEPATH$DAY/$SHORT_NAME.$timestamp.tar

#start backup on client
ssh $SHORT_NAME sudo tar -cvf - --exclude=/dev --exclude=/lost+found --exclude=/proc / |netcat -w 2 -c troll 2011



The first line starting gnetcat on the backup seerver works fine, however I have not been able to get the second line, sent to the client, to work.

#start gnetcat on backup server
system `gnetcat -l -vv -p 2011`, ">", "$filename";
#start backup on client
system `ssh $SHORT_NAME sudo tar -cvf - --exclude=/dev --exclude=/lost+found --exclude=/proc --exclude=/db / |netcat -w 4 -c troll 2011`;

Any help pointing out what I am doing wrong is greatly appreciated.

What do you exactly mean by "not work"? Normally, does the shell script prompt you password for ssh (or you bypass it based on "authorized_keys")?

I don't think you can use backticks in Perl if ssh gives a password prompt on connect. It may be fine for telnet or the like but likely to fail for ssh.

You may also try the more "native" Perl way of doing it -- use Perl modules for SSH. Note that you need to install that module if you intend to use it. A C compiler may be needed for installation. Given so many dependencies the easiest way of installing is by "cpan".

http://search.cpan.org/~dbrobins/Net...et/SSH/Perl.pm

By not working I meant that the client machine apparently never received the tar command, the problem was not ssh based, the code was working as a bash script, it was just the transition from bash to perl that was giving me problems.

You were right about not using the backticks, the code I finally wound up with that worked is
In researching using ssh via the system call I learned that quoting the entire command in one set of double quotes sends the command as a single string, instead of as a command with arguments. Each command and each argument has to be defined by enclosing them in double quotes separated by a comma. The part that took the most head scratching was the "/|". The / is part of the tar command that essentially sends the output to STDOUT. The pipe then sends it to netcat. However for the / and | to be recognized as sending the STDOUT to a pipe they have to be placed together as a unit enclosed in quotes.

It appeared to be such a small task, only two lines of code, that it didnt seem appropriate to use a module. Oh well, I did learn a fair amount about using system calls with ssh.

To cbkihong: Thanks for the reply, it got me pointed in the right direction to figure out what the problem was.