Detailed explanation of Linux startup program or script

Many times we need to set some services or scripts to start automatically on Linux, so as to avoid service interruption and other problems caused by machine restart. Let’s take a look at how to set up auto-start under Linux:

cd /etc/init.d vi myscript.sh #将myscript.sh修改为你自己的脚本名

Write your own script, save and exit.

When writing a script, please first add the following comments

#add for chkconfig  
#description:  #关于脚本的简短描述

Description:

2345 refers to the running level of the script, that is, in 2345 can be run in these four modes, 234 is a text interface, and 5 is a graphical interface. X

70 refers to the future startup sequence number of the script. If the startup sequence number of other programs is smaller than 70 (such as 44 , 45), the script needs to wait until these programs are started before starting.

30 refers to the stop sequence number of the script when the system is shut down.

Add executable permissions to the script:

chmod +x myscript.sh

Use the chkconfig command to set the script to self-start

chkconfig --add servicename

So that your script can run automatically after booting.

In addition, this method can also be used in redhat to achieve automatic startup at boot.

How to use chkconfig

chkconfig(check config)

Function description: Check and set various services of the system.

Syntax: chkconfig

[--add][--del][--list][system service] or chkconfig[--level89a30973f4a91be93336342cc6cbc0f5][system service] [on/off/reset]

Additional explanation: This is a program developed by RedHat in compliance with GPL rules. It can query what system services the operating system will execute in each execution level, including Various resident services.

Parameters:

-add Add the specified system service so that the chkconfig command can manage it, and at the same time add relevant data to the system startup narrative file.

　–del Delete the specified system service, which is no longer managed by the chkconfig command, and delete related data in the system startup narrative file at the same time.

　–level89a30973f4a91be93336342cc6cbc0f5 Specifies the execution level in which the reading system service should be turned on or off

1: The chkconfig command can also be used to activate and deactivate services. The chkconfig –list command displays a list of system services and whether they have been started (on) or stopped (off) in runlevels 0 to 6.

chkconfig –list
chkconfig –list httpd
httpd 0:off 1:off 2:on 3:on 4:on 5:on 6:off

2: chkconfig can also be used to set whether a service is started or stopped in a specified run level. For example, to stop the nscd service in runlevels 3, 4, and 5, use the following command:

chkconfig –level 345 nscd off

3: Services managed by xinetd will be immediately affected by chkconfig. For example, if xinetd is running and finger is disabled, then after executing the chkconfig finger on command, finger does not have to manually restart xinetd to be enabled immediately. Changes to other services do not take effect immediately after using chkconfig. You must use the service servicename start/stop/restart command to restart the service

Second method

Edit the /etc/rc.d/rc.local file

The format is program name program path

For example a.sh /home/a.sh

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