Change hostname with a variable with for loop

Question

I am trying to change the "hostname --transient" to some computers with a for loop using a variable. I want it to collect the "hostname -f" from the server itself and, using the variable, change it automatically. When I run it, it tells me "Invalid number of arguments."

Command:

for i in `cat /tmp/serverlist`; do echo "Hostname in $i" ssh -o StrictHostKeyChecking=no root@$i "hostname=$(hostname -f); hostnamectl --transient set-hostname $hostname" done 

Answer 1

Because you are using double quotes, the $hostname variable is being expanded on your local machine, before launching ssh, so it s presumably empty. You can get the same error with:

$ hostnamectl --transient set-hostname Too few arguments. 

Since you want these to be expanded on the remote host, use single quotes instead (also fixing a couple of other bad practices):

while IFS= read -r i; do ssh -o StrictHostKeyChecking=no "root@$i" 'hostnamectl --transient set-hostname "$(hostname -f)"' done