In Bash script trying to pass local variable to SSH and then execute the other commands - arrays

Question

#!/bin/bash
count2=1
declare -a input
input=( "$#" )
echo " "
echo " Hostname passed by user is " ${input[0]}
HOST="${input[0]}"
sshpass -p '<pass>' ssh -o StrictHostKeyChecking=no user#$HOST /bin/bash << ENDSSH
echo " Connected "
echo $count2
echo $input
pwd
echo $count2: ${input[$count2]}
nic=${input[$count2]}
echo $nic
echo $(ethtool "${nic}" |& grep 'Link' | awk '{print $3}')
ENDSSH
So Actually want to pass variable 'count2' and 'input' to remote SSH and execute.
But unfortunately it is not getting passed. It is not echoing anything after SSH.
Need help in this.!!
I have sshpass installed in sever.
code output:
[user#l07 ~]$ ./check.sh <hostname> eno6
Hostname passed by user is <hostname>
Connected
After SSH it only echos "Connected". I'm not sure why $count2 and $input is not echoing.
I tired with backlash '\$count2' but that is also not working. All possible combination tried even with quote and unquote of ENDSSH. Pls help
Any help will be really appreciated!!

Answer 1

You basically want to supply to your remote bash a HERE-document to be executed. This is tricky, since you need to "compose" the full text of this document before you can supply it to ssh. I would therefore separate the task into two parts:
Creating the HERE-document
Running it on ssh
This makes it easy for debugging to output the document between steps 1 and 2 and to visually inspect its contents for correctness. Don't forget that once this code runs on the remote host, it can't access any of your variables anymore, unless you have "promoted" them to the remote side using the means provided by ssh.
Hence you could start like this:
# Create the parameters you want to use
nic=${input[$count2]}
# Create a variable holding the content of the remote script,
# which interpolates your parameters
read -r -d '' remote_script << ENDSSH
echo "Connected to host \$(hostname)"
echo "Running bash version: \$BASH_VERSION"
....
ethtool "$nic" |& grep Link | awk '{ print $3 }'
ENDSSH
# Print your script for verification
echo "$remote_script"
# Submit it to the host
sshpass -p '<pass>' ssh -o StrictHostKeyChecking=no "user#$HOST" /bin/bash <<<"$remote_script"

Answer 2

You have to add escapes(\) here:
...
echo \$nic
...
echo \$(ethtool "\${nic}" |& grep 'Link' | awk '{print \$3}')
...
But why echoing this? Try it without echo
...
ethtool "\${nic}" |& grep -i 'Link' | awk '{print \$3}'
...

Answer 3

#!/bin/bash
count2=1
declare -a input
input=( "$#" )
echo " Hostname passed by user is " "${input[0]}"
HOST="${input[0]}"
while [ $# -gt $count2 ]
do
sed -i 's/VALUE/'"${input[$count2]}"'/g' ./check.sh
sshpass -p '<pass>' scp ./check.sh user#"$HOST":/home/user/check.sh
sshpass -p '<pass>' ssh -o StrictHostKeyChecking=no user#"$HOST" "sh /home/user/check.sh && rm -rf /home/user/check.sh"
sed -i 's/'"${input[$count2]}"'/VALUE/g' ./check.sh
((count2++))
done
Found the another solution of this issue: It is working for me now !!!!
I wrote my entire logic which needs to be executed remotely in check.sh file and now replacing or storing the user input into this check.sh file and copying this file into remote server via scp and executing it over remotely and after successful execution removing this file from remote server and after ssh , again changing the user input to it's original value in local server using sed command.
Made this as dynamic script to work for multiple servers.