Маленькая заметка про GREP — удаляем комментарии

Время на прочтение: 3 минут(ы)

В наше время уже редко, но приходится иногда сталкиваться с такой проблемой как чтение конфигурационных файлов и их правка. Часто многие из них хорошо документированные, что с одной стороны хорошо можно почерпнуть всегда нужную информацию по тем или иным переменным, но с другой стороны, вызывает проблемы с поиском и чтением подобных файлов.

Для того чтоб получить чистый вывод файла можно использовать утилиту grep в сочетании с регулярными выражениями она достаточно просто решает подобную задачу.

Например у нас есть вот такой вот файл конфигурации сервера MariaDB:

# cat /etc/mysql/mariadb.conf.d/50-server.cnf
#
# These groups are read by MariaDB server.
# Use it for options that only the server (but not clients) should see
#
# See the examples of server my.cnf files in /usr/share/mysql/
#

# this is read by the standalone daemon and embedded servers
[server]

# this is only for the mysqld standalone daemon
[mysqld]

#
# * Basic Settings
#
user            = mysql
pid-file        = /var/run/mysqld/mysqld.pid
socket          = /var/run/mysqld/mysqld.sock
port            = 3306
basedir         = /usr
datadir         = /var/lib/mysql
tmpdir          = /tmp
lc-messages-dir = /usr/share/mysql
skip-external-locking

# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
bind-address            = 127.0.0.1

#
# * Fine Tuning
#
key_buffer_size         = 16M
max_allowed_packet      = 16M
thread_stack            = 192K
thread_cache_size       = 8
# This replaces the startup script and checks MyISAM tables if needed
# the first time they are touched
myisam_recover_options  = BACKUP
#max_connections        = 100
#table_cache            = 64
#thread_concurrency     = 10

#
# * Query Cache Configuration
#
query_cache_limit       = 1M
query_cache_size        = 16M

#
# * Logging and Replication
#
# Both location gets rotated by the cronjob.
# Be aware that this log type is a performance killer.
# As of 5.1 you can enable the log at runtime!
#general_log_file        = /var/log/mysql/mysql.log
#general_log             = 1
#
# Error log - should be very few entries.
#
log_error = /var/log/mysql/error.log
#
# Enable the slow query log to see queries with especially long duration
#slow_query_log_file    = /var/log/mysql/mariadb-slow.log
#long_query_time = 10
#log_slow_rate_limit    = 1000
#log_slow_verbosity     = query_plan
#log-queries-not-using-indexes
#
# The following can be used as easy to replay backup logs or for replication.
# note: if you are setting up a replication slave, see README.Debian about
#       other settings you may need to change.
#server-id              = 1
#log_bin                        = /var/log/mysql/mysql-bin.log
expire_logs_days        = 10
max_binlog_size   = 100M
#binlog_do_db           = include_database_name
#binlog_ignore_db       = exclude_database_name

#
# * InnoDB
#
# InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/.
# Read the manual for more InnoDB related options. There are many!

#
# * Security Features
#
# Read the manual, too, if you want chroot!
# chroot = /var/lib/mysql/
#
# For generating SSL certificates you can use for example the GUI tool "tinyca".
#
# ssl-ca=/etc/mysql/cacert.pem
# ssl-cert=/etc/mysql/server-cert.pem
# ssl-key=/etc/mysql/server-key.pem
#
# Accept only connections using the latest and most secure TLS protocol version.
# ..when MariaDB is compiled with OpenSSL:
# ssl-cipher=TLSv1.2
# ..when MariaDB is compiled with YaSSL (default in Debian):
# ssl=on

#
# * Character sets
#
# MySQL/MariaDB default is Latin1, but in Debian we rather default to the full
# utf8 4-byte character set. See also client.cnf
#
character-set-server  = utf8mb4
collation-server      = utf8mb4_general_ci

#
# * Unix socket authentication plugin is built-in since 10.0.22-6
#
# Needed so the root database user can authenticate without a password but
# only when running as the unix root user.
#
# Also available for other users if required.
# See https://mariadb.com/kb/en/unix_socket-authentication-plugin/

# this is only for embedded server
[embedded]

# This group is only read by MariaDB servers, not by MySQL.
# If you use the same .cnf file for MySQL and MariaDB,
# you can put MariaDB-only options here
[mariadb]

# This group is only read by MariaDB-10.1 servers.
# If you use the same .cnf file for MariaDB of different versions,
# use this group for options that older servers don't understand
[mariadb-10.1]

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# cat /etc/mysql/mariadb.conf.d/50-server.cnf

# These groups are read by MariaDB server.

# Use it for options that only the server (but not clients) should see

# See the examples of server my.cnf files in /usr/share/mysql/

# this is read by the standalone daemon and embedded servers

[server]

# this is only for the mysqld standalone daemon

[mysqld]

# * Basic Settings

user = mysql

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

socket = /var/run/mysqld/mysqld.sock

port = 3306

basedir = /usr

datadir = /var/lib/mysql

tmpdir = /tmp

lc-messages-dir = /usr/share/mysql

skip-external-locking

# Instead of skip-networking the default is now to listen only on

# localhost which is more compatible and is not less secure.

bind-address = 127.0.0.1

# * Fine Tuning

key_buffer_size = 16M

max_allowed_packet = 16M

thread_stack = 192K

thread_cache_size = 8

# This replaces the startup script and checks MyISAM tables if needed

# the first time they are touched

myisam_recover_options = BACKUP

#max_connections = 100

#table_cache = 64

#thread_concurrency = 10

# * Query Cache Configuration

query_cache_limit = 1M

query_cache_size = 16M

# * Logging and Replication

# Both location gets rotated by the cronjob.

# Be aware that this log type is a performance killer.

# As of 5.1 you can enable the log at runtime!

#general_log_file = /var/log/mysql/mysql.log

#general_log = 1

# Error log - should be very few entries.

log_error = /var/log/mysql/error.log

# Enable the slow query log to see queries with especially long duration

#slow_query_log_file = /var/log/mysql/mariadb-slow.log

#long_query_time = 10

#log_slow_rate_limit = 1000

#log_slow_verbosity = query_plan

#log-queries-not-using-indexes

# The following can be used as easy to replay backup logs or for replication.

# note: if you are setting up a replication slave, see README.Debian about

# other settings you may need to change.

#server-id = 1

#log_bin = /var/log/mysql/mysql-bin.log

expire_logs_days = 10

max_binlog_size = 100M

#binlog_do_db = include_database_name

#binlog_ignore_db = exclude_database_name

# * InnoDB

# InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/.

# Read the manual for more InnoDB related options. There are many!

# * Security Features

# Read the manual, too, if you want chroot!

# chroot = /var/lib/mysql/

# For generating SSL certificates you can use for example the GUI tool "tinyca".

# ssl-ca=/etc/mysql/cacert.pem

# ssl-cert=/etc/mysql/server-cert.pem

# ssl-key=/etc/mysql/server-key.pem

# Accept only connections using the latest and most secure TLS protocol version.

# ..when MariaDB is compiled with OpenSSL:

# ssl-cipher=TLSv1.2

# ..when MariaDB is compiled with YaSSL (default in Debian):

# ssl=on

# * Character sets

# MySQL/MariaDB default is Latin1, but in Debian we rather default to the full

# utf8 4-byte character set. See also client.cnf

character-set-server = utf8mb4

collation-server = utf8mb4_general_ci

# * Unix socket authentication plugin is built-in since 10.0.22-6

# Needed so the root database user can authenticate without a password but

# only when running as the unix root user.

# Also available for other users if required.

# See https://mariadb.com/kb/en/unix_socket-authentication-plugin/

# this is only for embedded server

[embedded]

# This group is only read by MariaDB servers, not by MySQL.

# If you use the same .cnf file for MySQL and MariaDB,

# you can put MariaDB-only options here

[mariadb]

# This group is only read by MariaDB-10.1 servers.

# If you use the same .cnf file for MariaDB of different versions,

# use this group for options that older servers don't understand

[mariadb-10.1]

Портянка довольно солидная, как минимум без скроллинга никак не прочитать. Но если воспользоваться утилитой grep, то она приобретает следующий вид:

#  grep -Ev '^\s*(;|#|$)' /etc/mysql/mariadb.conf.d/50-server.cnf
[server]
[mysqld]
user            = mysql
pid-file        = /var/run/mysqld/mysqld.pid
socket          = /var/run/mysqld/mysqld.sock
port            = 3306
basedir         = /usr
datadir         = /var/lib/mysql
tmpdir          = /tmp
lc-messages-dir = /usr/share/mysql
skip-external-locking
bind-address            = 127.0.0.1
key_buffer_size         = 16M
max_allowed_packet      = 16M
thread_stack            = 192K
thread_cache_size       = 8
myisam_recover_options  = BACKUP
query_cache_limit       = 1M
query_cache_size        = 16M
log_error = /var/log/mysql/error.log
expire_logs_days        = 10
max_binlog_size   = 100M
character-set-server  = utf8mb4
collation-server      = utf8mb4_general_ci
[embedded]
[mariadb]
[mariadb-10.1]

# grep -Ev '^\s*(;|#|$)' /etc/mysql/mariadb.conf.d/50-server.cnf