SSH Bash script issues with if statement - linux

Question

I'm trying to learn how to write Bash scripts. I have this script to update my servers through ssh. I'm trying to add a check and a conditional to determine if the OS uses Yum or Apt then it will run the appropriate update commands. The if else statement seems to be wrong but I'm not sure how to correct this.
Here is the script:
#!/bin/bash
USERNAME="root"
HOSTS="host1 host2 host3"
apt_run="apt update && apt -y upgrade"
yum_run="yum check-update && yum -y update"
for HOSTNAME in ${HOSTS} ; do
ssh -l ${USERNAME} ${HOSTNAME}
find_os=$( command -v yum || command -v apt-get ) || echo "Neither
yum nor apt-get found"
if [[ $find_os='yum' ]]
then
"${yum_run}"
else
"${apt_run}"
fi
done

Answer 1

Here is my script for my virtual machines.
#!/bin/bash
hosts=(
leap151 kali ubuntu omv
)
for hostname in "${hosts[#]}"; do
ssh -t root#"$hostname" << 'EOF'
if type -P zypper >/dev/null; then
command zypper ref && command zypper up
elif type -P apt-get >/dev/null; then
command apt-get update && command apt-get upgrade
else
echo 'Neither zypper nor apt found!' >&2
exit 127
fi
EOF
done
Use an array for the host. Since you're using bash the builtin type is fine just for searching the executable within your PATH. See help type for more info. Use the -t option in ssh also use a heredoc just what I have/did. The exit 127 is what the shell would exit if there are no executable see man 1p exit.