Migrate user accounts from linux server to another linux server

ref.: http://www.cyberciti.biz/faq/howto-move-migrate-user-accounts-old-to-new-server/

Backup
# mkdir /root/move/
# export UGIDLIMIT=500

# awk -v LIMIT=$UGIDLIMIT -F: '($3>=LIMIT) && ($3!=65534)' /etc/passwd > /root/move/passwd.mig
# awk -v LIMIT=$UGIDLIMIT -F: '($3>=LIMIT) && ($3!=65534)' /etc/group > /root/move/group.mig
# awk -v LIMIT=$UGIDLIMIT -F: '($3>=LIMIT) && ($3!=65534) {print $1}' /etc/passwd | tee - |egrep -f - /etc/shadow > /root/move/shadow.mig
# cp /etc/gshadow /root/move/gshadow.mig
# tar -zcvpf /root/move/home.tar.gz /home
# tar -zcvpf /root/move/mail.tar.gz /var/spool/mail

Restore

# mkdir /root/newsusers.bak
# cp /etc/passwd /etc/shadow /etc/group /etc/gshadow /root/newsusers.bak
# cd /path/to/location
# cat passwd.mig >> /etc/passwd
# cat group.mig >> /etc/group
# cat shadow.mig >> /etc/shadow
# /bin/cp gshadow.mig /etc/gshadow
# cd /
# tar -zxvf /path/to/location/home.tar.gz


# cd /
# tar -zxvf /path/to/location/mail.tar.gz
# reboot