编写开机自动启动服务脚本：
# cat >> /usr/lib/systemd/system/postgresql.service >> EOF
[Unit]
Description=PostgreSQL database server
After=network.target
[Service]
Type=forking
User=postgres
Group=postgres
# Port number for server to listen on
Environment=PGPORT=5432
# Location of database directory
Environment=PGDATA=/usr/local/pgsql9.4/data
# Where to send early-startup messages from the server (before the logging
# options of postgresql.conf take effect)
# This is normally controlled by the global default set by systemd
# StandardOutput=syslog
# Disable OOM kill on the postmaster
OOMScoreAdjust=-1000
#ExecStartPre=/usr/local/pgsql9.4/bin/postgresql-check-db-dir ${PGDATA}
ExecStart=/usr/local/pgsql9.4/bin/pg_ctl start -D ${PGDATA} -s -o "-p ${PGPORT}" -w -t 300
ExecStop=/usr/local/pgsql9.4/bin/pg_ctl stop -D ${PGDATA} -s -m fast
ExecReload=/usr/local/pgsql9.4/bin/pg_ctl reload -D ${PGDATA} -s
# Give a reasonable amount of time for the server to start up/shut down
TimeoutSec=300
[Install]
WantedBy=multi-user.target
EOF
添加可执行权限：
chmod 754 /usr/lib/systemd/system/postgresql.service
设置为开机自启动：
systemctl enable postgresql.service
常用指令(以postgresql服务为例)：
启动某服务:
systemctl start postgresql.service
停止某服务:
systemctl stop postgresql.service
重启某服务:
systemctl restart postgresql.service service postgresql restart
使某服务自动启动(如tomcat服务):
systemctl enable postgresql.service
使某服务不自动启动:
systemctl disable postgresql.service
检查服务状态:
systemctl status postgresql.service （服务详细信息） systemctl is-active postgresql.service（仅显示是否Active)
显示所有已启动的服务:
systemctl list-units --type=service