Bash非交互式mysql数据库创建问题

Question

我有一个bash脚本，它利用对话框在非交互式Mysql数据库创建过程中显示进度条。

系统OS: Ubuntu 20.04服务器Mariadb: 10.5

The问题：只执行第一个Mysql命令(即创建数据库)，如果是其他命令，则是Error 1064。

#!/usr/bin/env bash
export NCURSES_NO_UTF8_ACS=1
var_db() {
    pfx=$(shuf -zer -n2 {a..z} | tr -d '\0')
    vnum=$(shuf -i 8-11 -n 1)
    sfx=$(openssl rand -base64 32 | tr -d /=+ | cut -c -"$vnum")
    varnam="${pfx}_${sfx}"
    echo "$varnam"
}
site_db() {
    dbname=$(var_db)
    userdb=$(var_db)
    vnum=$(shuf -i 12-15 -n 1)
    passdb=$(openssl rand -base64 32 | tr -d /=+ | cut -c -"$vnum")
    msgs=('Database created'
    'Database user created'
    'All privileges granted on database to user'
    'Reload privilege tables'
    'Restart Mariadb'
    'Reload Mariadb'
        )
    commands=('sudo mysql -e "CREATE DATABASE ${dbname};"'
    'sudo mysql -e "CREATE USER ${userdb}@localhost IDENTIFIED BY '${passdb}';"'
    'sudo mysql -e "GRANT ALL PRIVILEGES ON ${dbname}.* TO '${userdb}'@'localhost';"'
    'sudo mysql -e "FLUSH PRIVILEGES;"'
    'sudo systemctl restart mariadb'
    'sudo systemctl reload mariadb'
            )
    n=${#commands[@]}
    i=0
    while [ "$i" -le "$n" ]; do
        pct=$(( i * 100 / n )) # calculating progress percentage
        if [ $pct -eq 100 ]; then
            echo -e "XXX\n100\nMariadb secure installation completed!\nXXX"
        else
            echo -e "XXX\n$i\n${msgs[i]}\nXXX"
        fi
        echo "$pct"
        eval "${commands[i]}" > /dev/null 2>&1 #eval the output of the commands, 
        i=$((i + 1))
        sleep 2
    done | dialog --keep-tite --title "Site database configuration" --gauge "Site database created" 20 100 0
}
site_db

However，如果我不使用数组中的命令，那么所有的mysql命令都会在下面的脚本中执行。那么，为什么上面的脚本中有一个错误1064呢？

#!/usr/bin/env bash
var_db() {
    pfx=$(shuf -zer -n2 {a..z} | tr -d '\0')
    vnum=$(shuf -i 8-11 -n 1)
    sfx=$(openssl rand -base64 32 | tr -d /=+ | cut -c -"$vnum")
    varnam="${pfx}_${sfx}"
    echo "$varnam"
}
site_db() {
    dbname=$(var_db)
    userdb=$(var_db)
    vnum=$(shuf -i 12-15 -n 1)
    passdb=$(openssl rand -base64 32 | tr -d /=+ | cut -c -"$vnum")
    sudo mysql -e "CREATE DATABASE ${dbname};"
    sudo mysql -e "CREATE USER ${userdb}@localhost IDENTIFIED BY '${passdb}';"
    sudo mysql -e "GRANT ALL PRIVILEGES ON ${dbname}.* TO '${userdb}'@'localhost';"
    sudo mysql -e "FLUSH PRIVILEGES;"
    sudo systemctl restart mariadb
            )
}
site_db

Answer 1

这个问题与数组无关；它是引用。

userdb=userdb_value
passdb=passdb_value
set -x

eval echo 'sudo mysql -e "CREATE USER ${userdb}@localhost IDENTIFIED BY '${passdb}';"'
+ eval echo 'sudo mysql -e "CREATE USER ${userdb}@localhost IDENTIFIED BY passdb_value;"'
++ echo sudo mysql -e 'CREATE USER userdb_value@localhost IDENTIFIED BY passdb_value;'
sudo mysql -e CREATE USER userdb_value@localhost IDENTIFIED BY passdb_value;

echo sudo mysql -e "CREATE USER ${userdb}@localhost IDENTIFIED BY '${passdb}';"
+ echo sudo mysql -e 'CREATE USER userdb_value@localhost IDENTIFIED BY '\''passdb_value'\'';'
sudo mysql -e CREATE USER userdb_value@localhost IDENTIFIED BY 'passdb_value';

如果您可以使用"而不是'是SQL，那么您可以这样做：

'sudo mysql -e "CREATE USER ${userdb}@localhost IDENTIFIED BY \"${passdb}\";"'

如果没有的话，你可以这么做

'sudo mysql -e "CREATE USER ${userdb}@localhost IDENTIFIED BY '\''${passdb}'\'';"'

或

"sudo mysql -e \"CREATE USER ${userdb}@localhost IDENTIFIED BY '${passdb}';\""

或

quote=\'
'sudo mysql -e "CREATE USER ${userdb}@localhost IDENTIFIED BY ${quote}${passdb}${quote};"'