bash - 有谁知道仅使用 BaSH 在没有 vim、emacs 或 nano 的情况下编辑文本文件的绝妙技巧？

Question

对于上下文，我正在尝试为 MySQL DB 创建一个 docker 镜像，我可以在不使用密码的情况下登录。我正在阅读 article关于如何做到这一点，但它需要我使用我需要的凭据更新容器中的 my.cnf 以避免需要密码。
我的一个想法是获取 my.cnf 文件的样板版本，将其放入普通文本文件中，使用我需要的凭据对其进行更新，然后将其复制到容器中。但是我仍然不知道足够的 BASH 命令来从一个文件中获取文本并覆盖另一个文件。我什至只接受关于如何使用 vanilla shell 命令来完成它的指针。希望这可以帮助其他人发布此问题。
这是 my.cnf 本地人最初喜欢的内容

[mysqld]
#
# Remove leading # and set to the amount of RAM for the most important data
# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
# innodb_buffer_pool_size = 128M
#
# Remove leading # to turn on a very important data integrity option: logging
# changes to the binary log between backups.
# log_bin
#
# Remove leading # to set options mainly useful for reporting servers.
# The server defaults are faster for transactions and fast SELECTs.
# Adjust sizes as needed, experiment to find the optimal values.
# join_buffer_size = 128M
# sort_buffer_size = 2M
# read_rnd_buffer_size = 2M
skip-host-cache
skip-name-resolve
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
secure-file-priv=/var/lib/mysql-files
user=mysql

# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0

log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

我需要更新它以获得这样的东西。此代码段包含用户和密码行项目。

[mysqld]
#
# Remove leading # and set to the amount of RAM for the most important data
# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
# innodb_buffer_pool_size = 128M
#
# Remove leading # to turn on a very important data integrity option: logging
# changes to the binary log between backups.
# log_bin
#
# Remove leading # to set options mainly useful for reporting servers.
# The server defaults are faster for transactions and fast SELECTs.
# Adjust sizes as needed, experiment to find the optimal values.
# join_buffer_size = 128M
# sort_buffer_size = 2M
# read_rnd_buffer_size = 2M
skip-host-cache
skip-name-resolve
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
secure-file-priv=/var/lib/mysql-files
user=mysql

# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0

log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
[MySQL]
user=root
password=supersecret

Answer 1

由于您想要进行的更改只是添加到文件的末尾，因此您可以使用带有 >> 的输出重定向。附加到文件中。以下任何一项都应该有效。下面是一个使用 shell “here-document”的例子:

cat >>.my.cnf <<'EOF'
[MySQL]
user=root
password=supersecret
EOF

或者您可以使用三个单独的 echo年代:

echo '[MySQL]' >>.my.cnf
echo 'user=root' >>.my.cnf
echo 'password=supersecret' >>.my.cnf

或单个 printf :

printf '%s\n' '[MySQL]' 'user=root' 'password=supersecret' >>.my.cnf

请注意，如果您的密码包含单引号，则需要在 echo 中进行更复杂的处理。或 printf案例(因为您不能在单引号字符串中包含单引号)。