SSH: remote variable

Question

I want to run a complex script via ssh

#!/bin/sh

ARRAY1=(
server1s
server123
server12
server14
server13
)


for i in ${ARRAY1[@]};do ssh  $i "
    case \$HOSTNAME in 

server1.domain.com)
echo try1
  ;;
server12.domain.com)
echo try12
  ;;
*)
echo try123
  ;;
esac

The problem is ssh read my internal hostname variable and return try123,is possible to read the internal variable of remote site? I have tried \$VARIABLE and $VARIABLE but result is the same

Answer 1

Using \$HOSTNAME is the correct way to escape the variable in this case.

However, that variable often contains the hostname (non-fqdn), or may not be populated. You should rather use the command hostname -f to get your server FQDN.

I don't know how will look like your final script, but connecting to server1 then check if this server is server1 may be some kind of useless (out of security purpose).

You could write some scripts, for instance script1.sh containing

echo "$HOSTNAME / $(hostname -f)"

then

for i in ${ARRAY1[@]};do
    case $i in
      server1) ssh $i < script1.sh
      ;;
      server2) ssh $i < script2.sh
      ;;
      *) ssh $i < script_${i}.sh
    esac
 done 

EDIT: As stated in comments, OpenBSD shipped version of hostname doesn't understand -f option. The default behaviour is to display FQDN.