UNIX for Dummies Questions & Answers

Hi all,

I am facing an issue while trying to access a for loop variable inside ssh. Can anyone please help me with what this issue is, the following is the code that I have ->

Code:

IMPL_LOG_FOLDERS=(transaction_logs invalid_transaction_logs)
 
sshg3 ftp_id@boxname << EOS
 
for log_folder in ${IMPL_LOG_FOLDERS[@]}
do
echo "my $log_folder ";
 
done
EOS

The $log_folder always prints blank. Now the script prints something like this ->

Code:

Last login: Tue May 10 2011 15:47:17 -0400 from boxname 
my 
my

This shows that the for loop is executing twice and hence it is able to read that variable IMPL_LOG_FOLDERS, what I am not understanding is why the varible log_folder can not be read from inside the for loop.

Any help regarding this will be greatly appreciated.

Try this:

Code:

cat <<EOF
for N in 1 2 3
do
        echo VAR:$N
done
EOF

You get:

Code:

for N in 1 2 3
do
        echo VAR:
done

because $N gets substituted before the text is even printed! You have to escape the $ to make it remain a $.

Code:

cat <<EOF
for N in 1 2 3
do
        echo VAR:\$N
done
EOF

Hi Corona688,
Thank you so much for the reply. It does work when I escape the $ , if you can please help me understand why the $N gets substituted it will be really great for my knowledge. Who substitutes that variable and makes it blank ?
Is it ssh who does that , if so why ...

Thanks again ...

The shell always interprets the $ prefixed names as variable, and in your current shell you may not have a variable N, so you will get null being replaced for $N and this code will be sent trough ssh

Finally the execution will not work in the remote machine.

But when you escape the $ , the shell doesn't do anything except removing the \ .

So in the remote machine it works fine.

for ssh I use puTTY its easier..

Hi kumaran_5555,

Thanks a lot for the explanation. Now I understand what the issue was.

Hi Okhawaja,

We in our project use the tectia ssh product. But thanks for the info , we will try to go through the putty secure ftp implementation.

Lastly , thanks all for your time and help in solving my problem. You guys rock