变量用双引号包起来

hostname=$(ifconfig | grep 'inet ' | grep -v '127.0.0.1' | grep -v '192.168' | awk '{print $2}' | cut -d: -f 2)

conns=$(netstat -antup | awk '$4 ~ /'"$hostname"':8080/ {print $0}' | awk '$5 !~ /'"$hostname"':.*/ {print $5}' |\
    cut -d ':' -f 1 | sort | uniq | awk 'ORS=" "')

if [ -n "$conns" ];then
echo '$hostname connected with clients: '
echo "$conns"
fi