请教下代码语法高亮 shell 和 bash 的区别在哪？

我需要编辑 shell 脚本的时候 bash 是有高亮的，它这便是怎么选择的。各位请问

#!bin/bash
NGX_FILES=Nginx-1.16.tar.gz
PHP_FILES=php5.3.3.tar.gz
NGX_SRC=`echo $NGX_FILES| sed 's/\.tar\.gz//g'`
DWN_URL="包链接地址"
MYSQL_FILES=mysql-5.1.17.tar.gz

function nginx_install()
{
 wget -c ${DWN_URL}/${NGX_SRC}
 tar -xzf $NGX_FILES; cd NGX_SRC;./configure ;make ;make install
 if [$0 -eq 0];then
    echo "The Nginx install success!"
 fi
}

function mysql_install()
{
    tar -xzf $MYSQL_FILES ;cd mysql-5.1.17 ;.configure --prefix=/usr/local/mysql; make;make install
}

function php_install()
{
    if [ -d /usr/local/mysql]; then
        sql=/usr/local/mysql; make; make install
    else
        echo "Please pre install Mysql."
    fi
}
PS3="Please Select your intsall Menu:"
select i in "Nginx" "Mysql" "PHP"
do
case $i in
            Nginx)
                nginx_install;;
            Mysql)
                mysql_install;;
            php)
                php_install;;
            *)
                echo "usage: $0{Nginx | Mysql | PHP | help}"
                ;;
esac
done

还有 shell 语法高亮

#!bin/bash
NGX_FILES=Nginx-1.16.tar.gz
PHP_FILES=php5.3.3.tar.gz
NGX_SRC=`echo $NGX_FILES| sed 's/\.tar\.gz//g'`
DWN_URL="包链接地址"
MYSQL_FILES=mysql-5.1.17.tar.gz

function nginx_install()
{
 wget -c ${DWN_URL}/${NGX_SRC}
 tar -xzf $NGX_FILES; cd NGX_SRC;./configure ;make ;make install
 if [$0 -eq 0];then
    echo "The Nginx install success!"
 fi
}

function mysql_install()
{
    tar -xzf $MYSQL_FILES ;cd mysql-5.1.17 ;.configure --prefix=/usr/local/mysql; make;make install
}

function php_install()
{
    if [ -d /usr/local/mysql]; then
        sql=/usr/local/mysql; make; make install
    else
        echo "Please pre install Mysql."
    fi
}
PS3="Please Select your intsall Menu:"
select i in "Nginx" "Mysql" "PHP"
do
case $i in
            Nginx)
                nginx_install;;
            Mysql)
                mysql_install;;
            php)
                php_install;;
            *)
                echo "usage: $0{Nginx | Mysql | PHP | help}"
                ;;
esac
done