Shell Tips: Menghilangkan Komentar dan Baris Kosong pada Konfigurasi

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Shell menghilangkan komentar dan baris kosong
Grep untuk menghilangkan komentar dan baris kosong

TeknoCerdas.com – Salam cerdas untuk kita semua. Sebagai Sysadmin atau orang yang mengurusi server tentu akrab dengan berbagai macam konfigurasi file dari berbagai aplikasi. Sebut saja Apache, MySQL, Nginx, SSH, Redis dan masih banyak lagi. Biasanya pada setiap konfigurasi tersebut terdapat banyak komentar dan baris kosong.

Saat melakukan debugging, terkadang kita tidak ingin melihat itu semua karena ingin fokus pada konfigurasi yang diterapkan.

Tips singkat pada tulisan ini akan menghilangkan komentar dan baris kosong pada beberapa konfigurasi file yang umum ditemukan pada aplikasi server.

Baca Juga
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Menghilangkan Komentar Berawalan #

Sebagian besar aplikasi server seperti Apache, Nginx dan SSH menggunakan tanda pagar # sebagai awalan untuk menandakan komentar. Berikut adalah contoh konfigurasi file dari Nginx.

user www-data;
worker_processes auto;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;

events {
    worker_connections 768;
    # multi_accept on;
}

http {

    ##
    # Basic Settings
    ##

    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout 5;
    types_hash_max_size 2048;
    server_tokens off;
        client_max_body_size 128m;

    # server_names_hash_bucket_size 64;
    # server_name_in_redirect off;

    include /etc/nginx/mime.types;
    default_type application/octet-stream;

    ##
    # SSL Settings
    ##

    ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE
    ssl_prefer_server_ciphers on;

    ##
    # Logging Settings
    ##

    access_log /var/log/nginx/access.log;
    error_log /var/log/nginx/error.log;

    ##
    # Gzip Settings
    ##

    gzip on;

    # gzip_vary on;
    # gzip_proxied any;
    # gzip_comp_level 6;
    # gzip_buffers 16 8k;
    # gzip_http_version 1.1;
    # gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;

    ##
    # Virtual Host Configs
    ##

    include /etc/nginx/conf.d/*.conf;
    include /etc/nginx/sites-enabled/*;
}

Kita dapat menggunakan grep untuk menghilangkan komentar dan baris kosong.

$ grep -v '^#\|^\s*#\|^\s*$' nginx.conf
user www-data;
worker_processes auto;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;
events {
	worker_connections 768;
}
http {
	sendfile on;
	tcp_nopush on;
	tcp_nodelay on;
	keepalive_timeout 5;
	types_hash_max_size 2048;
	server_tokens off;
        client_max_body_size 128m;
	include /etc/nginx/mime.types;
	default_type application/octet-stream;
	ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE
	ssl_prefer_server_ciphers on;
	access_log /var/log/nginx/access.log;
	error_log /var/log/nginx/error.log;
	gzip on;
	include /etc/nginx/conf.d/*.conf;
	include /etc/nginx/sites-enabled/*;
}

Keterangan dari perintah diatas adalah:

  • -v untuk tidak menampilkan baris yang sesuai dengan regex.
  • ^ mengindikasikan HARUS diawali dengan.
  • | operator OR.
  • \ escape character untuk karakter khusus misal |.
  • ^# untuk menghilangkan komentar diawal.
  • ^\s*# untuk menghilangkan komentar yang didahului satu atau lebih whitespace (spasi atau tab).
  • ^\s*$ untuk menghilangkan baris kosong (satu atau lebih whitespace hingga akhir baris $).

Menghilangkan Komentar Berawalan ;

Selain tanda # karakter yang umum untuk digunakan sebagai komentar adalah ; titik-koma. Contoh-contoh aplikasi yang menggunakan model konfigurasi ini diantaranya: MySQL dan PHP.

Konfigurasi ini juga biasa disebut tipe ini file. Berikut ini adalah contoh konfigurasi dari PHP-FPM.

; Start a new pool named 'www'.
; the variable $pool can be used in any directive and will be replaced by the
; pool name ('www' here)
[www]

; Per pool prefix
; It only applies on the following directives:
; - 'access.log'
; - 'slowlog'
; - 'listen' (unixsocket)
; - 'chroot'
; - 'chdir'
; - 'php_values'
; - 'php_admin_values'
; When not set, the global prefix (or /usr) applies instead.
; Note: This directive can also be relative to the global prefix.
; Default Value: none
;prefix = /path/to/pools/$pool

; Unix user/group of processes
; Note: The user is mandatory. If the group is not set, the default user's group
;       will be used.
user = www-data
group = www-data

; The address on which to accept FastCGI requests.
; Valid syntaxes are:
;   'ip.add.re.ss:port'    - to listen on a TCP socket to a specific IPv4 address on
;                            a specific port;
;   '[ip:6:addr:ess]:port' - to listen on a TCP socket to a specific IPv6 address on
;                            a specific port;
;   'port'                 - to listen on a TCP socket to all addresses
;                            (IPv6 and IPv4-mapped) on a specific port;
;   '/path/to/unix/socket' - to listen on a unix socket.
; Note: This value is mandatory.
listen = /run/php/php7.2-fpm.sock

; Set listen(2) backlog.
; Default Value: 511 (-1 on FreeBSD and OpenBSD)
;listen.backlog = 511

; Set permissions for unix socket, if one is used. In Linux, read/write
; permissions must be set in order to allow connections from a web server. Many
; BSD-derived systems allow connections regardless of permissions.
; Default Values: user and group are set as the running user
;                 mode is set to 0660
listen.owner = www-data
listen.group = www-data
;listen.mode = 0660
; When POSIX Access Control Lists are supported you can set them using
; these options, value is a comma separated list of user/group names.
; When set, listen.owner and listen.group are ignored
;listen.acl_users =
;listen.acl_groups =

; List of addresses (IPv4/IPv6) of FastCGI clients which are allowed to connect.
; Equivalent to the FCGI_WEB_SERVER_ADDRS environment variable in the original
; PHP FCGI (5.2.2+). Makes sense only with a tcp listening socket. Each address
; must be separated by a comma. If this value is left blank, connections will be
; accepted from any ip address.
; Default Value: any
;listen.allowed_clients = 127.0.0.1

; Specify the nice(2) priority to apply to the pool processes (only if set)
; The value can vary from -19 (highest priority) to 20 (lower priority)
; Note: - It will only work if the FPM master process is launched as root
;       - The pool processes will inherit the master process priority
;         unless it specified otherwise
; Default Value: no set
; process.priority = -19

; Set the process dumpable flag (PR_SET_DUMPABLE prctl) even if the process user
; or group is differrent than the master process user. It allows to create process
; core dump and ptrace the process for the pool user.
; Default Value: no
; process.dumpable = yes

; Choose how the process manager will control the number of child processes.
; Possible Values:
;   static  - a fixed number (pm.max_children) of child processes;
;   dynamic - the number of child processes are set dynamically based on the
;             following directives. With this process management, there will be
;             always at least 1 children.
;             pm.max_children      - the maximum number of children that can
;                                    be alive at the same time.
;             pm.start_servers     - the number of children created on startup.
;             pm.min_spare_servers - the minimum number of children in 'idle'
;                                    state (waiting to process). If the number
;                                    of 'idle' processes is less than this
;                                    number then some children will be created.
;             pm.max_spare_servers - the maximum number of children in 'idle'
;                                    state (waiting to process). If the number
;                                    of 'idle' processes is greater than this
;                                    number then some children will be killed.
;  ondemand - no children are created at startup. Children will be forked when
;             new requests will connect. The following parameter are used:
;             pm.max_children           - the maximum number of children that
;                                         can be alive at the same time.
;             pm.process_idle_timeout   - The number of seconds after which
;                                         an idle process will be killed.
; Note: This value is mandatory.
pm = dynamic

; The number of child processes to be created when pm is set to 'static' and the
; maximum number of child processes when pm is set to 'dynamic' or 'ondemand'.
; This value sets the limit on the number of simultaneous requests that will be
; served. Equivalent to the ApacheMaxClients directive with mpm_prefork.
; Equivalent to the PHP_FCGI_CHILDREN environment variable in the original PHP
; CGI. The below defaults are based on a server without much resources. Don't
; forget to tweak pm.* to fit your needs.
; Note: Used when pm is set to 'static', 'dynamic' or 'ondemand'
; Note: This value is mandatory.
pm.max_children = 10

; The number of child processes created on startup.
; Note: Used only when pm is set to 'dynamic'
; Default Value: min_spare_servers + (max_spare_servers - min_spare_servers) / 2
pm.start_servers = 2

; The desired minimum number of idle server processes.
; Note: Used only when pm is set to 'dynamic'
; Note: Mandatory when pm is set to 'dynamic'
pm.min_spare_servers = 2

; The desired maximum number of idle server processes.
; Note: Used only when pm is set to 'dynamic'
; Note: Mandatory when pm is set to 'dynamic'
pm.max_spare_servers = 4

; The number of seconds after which an idle process will be killed.
; Note: Used only when pm is set to 'ondemand'
; Default Value: 10s
;pm.process_idle_timeout = 10s;

; The number of requests each child process should execute before respawning.
; This can be useful to work around memory leaks in 3rd party libraries. For
; endless request processing specify '0'. Equivalent to PHP_FCGI_MAX_REQUESTS.
; Default Value: 0
;pm.max_requests = 500

Kita dapat menggunakan grep yang sama seperti sebelumnya hanya perlu mengganti tanda # dengan ;.

$ grep -v '^;\|^\s*;\|^\s*$' fpm-www.conf
[www]
user = www-data
group = www-data
listen = /run/php/php7.2-fpm.sock
listen.owner = www-data
listen.group = www-data
pm = dynamic
pm.max_children = 10
pm.start_servers = 2
pm.min_spare_servers = 2
pm.max_spare_servers = 4