shell 执行方式

1.source(或者.)

当使用source运行脚本程序时,系统并不会创建子shell,而是将脚本中的命令放到shell父中运行

2.sh or bash

当使用sh或者bash运行shell脚本程序时,系统将创建一个子shell执行脚本中的命令

export 的作用是为当前shell设置环境变量,这样变量在其子shell也可以访问,当然,在其父shell中还是无法访问的

普通的变量只在当前shell中可以访问,在父shell或者子shell中都无法访问

3.后台运行脚本

命令 描述
monitor.sh & --shell终端断掉脚本就停止运行了
nohup command & --不挂断的执行程序
setsid command & --关闭shell终端,命令继续后台运行
(monitor.sh &) --关闭shell终端,命令继续后台运行
disown -h %1 --已经在运行的用户进程不受用户退出限制

4.开机执行脚本

rc.local

rc.local是在完成所有初始化之后执行,因此我们可以把启动脚本写到里面

init.d

init.d目录下都为可执行程序,他们其实是服务脚本,按照一定格式编写,Linux 在启动时会自动执行,类似Windows下的服务

eg:

1.在/etc/rc.d/init.d/目录下创建启动脚本

#!/bin/bash
### BEGIN INIT INFO
#
# Provides:     location_server
# Required-Start:    $local_fs  $remote_fs
# Required-Stop:    $local_fs  $remote_fs
# Default-Start:     2 3 4 5
# Default-Stop:     0 1 6
# Short-Description:    initscript
# Description:     This file should be used to construct scripts to be placed in /etc/init.d.
#
### END INIT INFO

## Fill in name of program here.
PROG="location_server"   # 所要执行程序的名称
PROG_PATH="/opt/location_server" # 可执行文件所在目录
helpful (if $PROG resides in /opt for example).
PROG_ARGS=""  # 执行程序需要的各个参数
PID_PATH="/var/run/"

start() {
    if [ -e "$PID_PATH/$PROG.pid" ]; then
        ## Program is running, exit with error.
        echo "Error! $PROG is currently running!" 1>&2
        exit 1
    else
        ## Change from /dev/null to something like /var/log/$PROG if you want to save output.
        $PROG_PATH/$PROG $PROG_ARGS 2>&1 >/var/log/$PROG &
    $pid=`ps ax | grep -i 'location_server' | sed 's/^\([0-9]\{1,\}\).*/\1/g' | head -n 1`

        echo "$PROG started"
        echo $pid > "$PID_PATH/$PROG.pid"
    fi
}

stop() {
    echo "begin stop"
    if [ -e "$PID_PATH/$PROG.pid" ]; then
        ## Program is running, so stop it
    pid=`ps ax | grep -i 'location_server' | sed 's/^\([0-9]\{1,\}\).*/\1/g' | head -n 1`
    kill $pid

        rm -f  "$PID_PATH/$PROG.pid"
        echo "$PROG stopped"
    else
        ## Program is not running, exit with error.
        echo "Error! $PROG not started!" 1>&2
        exit 1
    fi
}

## Check to see if we are running as root first.
## Found at http://www.cyberciti.biz/tips/shell-root-user-check-script.html
if [ "$(id -u)" != "0" ]; then
    echo "This script must be run as root" 1>&2
    exit 1
fi

case "$1" in
    start)
        start
        exit 0
    ;;
    stop)
        stop
        exit 0
    ;;
    reload|restart|force-reload)
        stop
        start
        exit 0
    ;;
    **)
        echo "Usage: $0 {start|stop|reload}" 1>&2
        exit 1
    ;;
esac

2.添加删除服务

添加: sudo update-rc.d 服务名 defaults

删除:sudo update-rc.d -f 服务名 remove

3.启动、关闭、重启服务

/etc/init.d/服务名 start

/etc/init.d/服务名 stop

/etc/init.d/服务名 start

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转载自www.cnblogs.com/jfxu/p/11986643.html