避免重复Bash中的变量设置

Question

在这里bash newbie！我如何避免重复“ passgen = $（＆lt;/dev/dev/urandom tr -dc _a-zaz-0-9 | head -c12）”？

sqlite variables.db "create table passwords (name TEXT PRIMARY KEY, value TEXT);"
PASSGEN=$(</dev/urandom tr -dc _A-Z-a-z-0-9 | head -c12)
sqlite variables.db "insert into passwords (name,value) values ('BOOKSTACK_MYSQL_ROOT', '$PASSGEN');"
PASSGEN=$(</dev/urandom tr -dc _A-Z-a-z-0-9 | head -c12)
sqlite variables.db "insert into passwords (name,value) values ('BOOKSTACK_MYSQL', '$PASSGEN');"
PASSGEN=$(</dev/urandom tr -dc _A-Z-a-z-0-9 | head -c12)
sqlite variables.db "insert into passwords (name,value) values ('BORG_PASSPHRASE', '$PASSGEN');"
PASSGEN=$(</dev/urandom tr -dc _A-Z-a-z-0-9 | head -c12)
sqlite variables.db "insert into passwords (name,value) values ('CODE_SERVER_PASS', '$PASSGEN');"
PASSGEN=$(</dev/urandom tr -dc _A-Z-a-z-0-9 | head -c12)
sqlite variables.db "insert into passwords (name,value) values ('CODE_SERVER_SUDO_PASS', '$PASSGEN');"
PASSGEN=$(</dev/urandom tr -dc _A-Z-a-z-0-9 | head -c12)
sqlite variables.db "insert into passwords (name,value) values ('EXPORTARR_TOKEN', '$PASSGEN');"
PASSGEN=$(</dev/urandom tr -dc _A-Z-a-z-0-9 | head -c12)
sqlite variables.db "insert into passwords (name,value) values ('FLAME_PASS', '$PASSGEN');"
PASSGEN=$(</dev/urandom tr -dc _A-Z-a-z-0-9 | head -c12)
sqlite variables.db "insert into passwords (name,value) values ('FLIGHTAIRMAP_INSTALL_PASS', '$PASSGEN');"

Answer 1

一个简单的解决方案是编写一个函数：

function generate_password {
    </dev/urandom tr -dc _A-Z-a-z-0-9 | head -c12
}

然后，您的代码段变为：

sqlite variables.db "create table passwords (name TEXT PRIMARY KEY, value TEXT);"
sqlite variables.db "insert into passwords (name,value) values ('BOOKSTACK_MYSQL_ROOT', '$(generate_password)');"
sqlite variables.db "insert into passwords (name,value) values ('BOOKSTACK_MYSQL', '$(generate_password)');"
sqlite variables.db "insert into passwords (name,value) values ('BORG_PASSPHRASE', '$(generate_password)');"
# ...

Answer 2

一种方法是将循环用于表插入。尝试此 shellCheck -clean代码：

sqlite variables.db "create table passwords (name TEXT PRIMARY KEY, value TEXT);"

for name in BOOKSTACK_MYSQL_ROOT BOOKSTACK_MYSQL BORG_PASSPHRASE    \
            CODE_SERVER_PASS CODE_SERVER_SUDO_PASS EXPORTARR_TOKEN  \
            FLAME_PASS FLIGHTAIRMAP_INSTALL_PASS
do
    passgen=$(</dev/urandom tr -dc _A-Z-a-z-0-9 | head -c12)
    sqlite variables.db "insert into passwords (name,value) values ('$name', '$passgen');"
done

• 请参阅正确的bash and shell脚本可变大写，以说明为什么我用passgen替换passgen。