Linux 如何使用init函数？

每个操作系统都有库。它们中的大多数让您有机会做更多的工作，编写更少的代码。 inti functions是这些库中的一个，但是

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什么是init函数以及如何使用它？

在Linux中，您可以使用init函数以彩色统一的方式管理deamons和protocol。这比回忆每一个答案更容易处理

它以init functions的名称存储在/lib/lsb/中

这里有一个例子：

#!/bin/bash
# Script by Amir Boudani                      ©Amir Boudani
source /lib/lsb/init-functions                  # Importing init-functions - log messages
                                # Use for importing other scripts ore else: "source" / "."
                                # Use at the beginning of the path "/" to say that the path has to start from the root directory

log_success_msg "Starting test.sh" || true
echo
log_action_msg "Info message" || true               # Info message
log_success_msg "Checking Files" || true            # Success message
log_warning_msg "Free storage is under 10%" || true         # Warning message
log_failure_msg "Starting unknown script files" || false    # Failure message

echo
log_end_msg 0 || true                       # End message - success - resetting the line above -> log_daemon_msg
log_end_msg 1 || true                       # End message - failure - resetting the line above -> log_daemon_msg
log_end_msg 255 || true                     # End message - warning - resetting the line above -> log_daemon_msg
echo
log_progress_msg "copying file 2123"                # One of the line resetting comands - progress
echo
echo

log_daemon_msg "Integrate files" || true
sleep 2
log_end_msg 0 || true

log_daemon_msg "Checkt if the directory 4234 exist" || true
sleep 2
log_end_msg 1 || true

log_daemon_msg "Storage space checking " || true
sleep 2
log_end_msg 255 || true
echo
echo
log_daemon_msg "Checking Filestorage" || true
sleep 1
log_progress_msg "Checking File 1"  || true
sleep 1
log_progress_msg "Checking File 2" || true
sleep 1
log_progress_msg "Checking File 3"  || true
sleep 1
log_progress_msg "Checking File 4"  || true
sleep 1
log_end_msg 0 || true

echo

#---------------------------------------------------------------# Method 1 - not working for commands that are self responding

$checker                            # A variable that doesn't exist. To trigger an error code
log_daemon_msg "Check if the last command was an Error" || true
if [ "$?" -eq "0" ]                         # "$?" is the errorcode number of the last command. | 0 = There was no Errors | 1 = Error code 1
then
    log_end_msg 0 || true
else
    log_end_msg 1 || true
    echo "       There went something wrong. see log"
fi

#---------------------------------------------------------------# A way to check if a directory exist

#if [ -d "/opt/scripts"  ]                  # Check if directory exist - example at this line: if directory /opt/scripts exist
                                # -d = check if the following directory exitst
                                # -a = check if the following file exsist
#if [ ! -d "/opt/scripts" ]                 # ! is a negativ operator - example at this line: if directory /opt/scripts NOT exist
                                # You can actually use the ! operator anywhere

#---------------------------------------------------------------# Method 2 - working for self responding commands. but the log_daemon_msg ist not working so we take log_succes/warning/failure_msg

echo
echo "type in: false / true / (nothing)"
read var1 
case $var1 in                           # Check if variable var1 is true
    true)
        log_success_msg "Check if var1 is true" || true
        ;;

    false)
                log_warning_msg "Check if var1 is true" || true
                echo -e "       \e[33mvar1 is false.\e[0m"
                ;;

    *)
            log_failure_msg "Check if var1 is true" || true
            echo -e "       \e[31mthere was no input in the read statment.\e[0m"
        ;;
esac

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init函数是SysV init的一个工件，一般来说，SysV init是一个过时的代码块，不应该用于新的开发。现代最佳实践是使用适当的流程监控系统systemd、upstart、runit、launchd等，而不是传统的init脚本。请参阅中的示例运行脚本，您会注意到它们通常总共不超过五行，因此根本不需要任何库支持。其他过程监控系统的配置可能不那么简洁，但它们使init功能过时和不相关是普遍的。