Question

我想从默认的nginx配置服务器配置文件中删除server {...}代码块。

sudo sed -i '/(\s*#?)server \s*{(?:[\s\S]+)\1}/ d' /opt/nginx/conf/nginx.conf

生成sed: -e expression #1, char 33: Invalid back reference

然而，使用像Rubular这样的工具，匹配工作正常。基本上我需要做的是根据匹配的缩进匹配代码块，否则会删除太多。

您可以使用默认的nginx配置作为测试字符串在Rubular中自行测试：

#user  nobody;
#Defines which Linux system user will own and run the Nginx server

worker_processes  1;
#Referes to single threaded process. Generally set to be equal to the number of CPUs or cores.

#error_log  logs/error.log; #error_log  logs/error.log  notice;
#Specifies the file where server logs. 

#pid        logs/nginx.pid;
#nginx will write its master process ID(PID).

events {
    worker_connections  1024;
    # worker_processes and worker_connections allows you to calculate maxclients value: 
    # max_clients = worker_processes * worker_connections
}


http {
    include       mime.types;
    # anything written in /opt/nginx/conf/mime.types is interpreted as if written inside the http { } block

    default_type  application/octet-stream;
    #

    #log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
    #                  '$status $body_bytes_sent "$http_referer" '
    #                  '"$http_user_agent" "$http_x_forwarded_for"';

    #access_log  logs/access.log  main;

    sendfile        on;
    # If serving locally stored static files, sendfile is essential to speed up the server,
    # But if using as reverse proxy one can deactivate it

    #tcp_nopush     on;
    # works opposite to tcp_nodelay. Instead of optimizing delays, it optimizes the amount of data sent at once.

    #keepalive_timeout  0;
    keepalive_timeout  65;
    # timeout during which a keep-alive client connection will stay open.

    #gzip  on;
    # tells the server to use on-the-fly gzip compression.

    server {
        # You would want to make a separate file with its own server block for each virtual domain
        # on your server and then include them.
        listen       80;
        #tells Nginx the hostname and the TCP port where it should listen for HTTP connections.
        # listen 80; is equivalent to listen *:80;

        server_name  localhost;
        # lets you doname-based virtual hosting

        #charset koi8-r;

        #access_log  logs/host.access.log  main;

        location / {
            #The location setting lets you configure how nginx responds to requests for resources within the server.
            root   html;
            index  index.html index.htm;
        }

        #error_page  404              /404.html;

        # redirect server error pages to the static page /50x.html
        #
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }

        # proxy the PHP scripts to Apache listening on 127.0.0.1:80
        #
        #location ~ \.php$ {
        #    proxy_pass   http://127.0.0.1;
        #}

        # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
        #
        #location ~ \.php$ {
        #    root           html;
        #    fastcgi_pass   127.0.0.1:9000;
        #    fastcgi_index  index.php;
        #    fastcgi_param  SCRIPT_FILENAME  /scripts$fastcgi_script_name;
        #    include        fastcgi_params;
        #}

        # deny access to .htaccess files, if Apache's document root
        # concurs with nginx's one
        #
        #location ~ /\.ht {
        #    deny  all;
        #}
    }


    # another virtual host using mix of IP-, name-, and port-based configuration
    #
    #server {
    #    listen       8000;
    #    listen       somename:8080;
    #    server_name  somename  alias  another.alias;

    #    location / {
    #        root   html;
    #        index  index.html index.htm;
    #    }
    #}


    # HTTPS server
    #
    #server {
    #    listen       443 ssl;
    #    server_name  localhost;

    #    ssl_certificate      cert.pem;
    #    ssl_certificate_key  cert.key;

    #    ssl_session_cache    shared:SSL:1m;
    #    ssl_session_timeout  5m;

    #    ssl_ciphers  HIGH:!aNULL:!MD5;
    #    ssl_prefer_server_ciphers  on;

    #    location / {
    #        root   html;
    #        index  index.html index.htm;
    #    }
    #}

}

Answer 1

sed不允许正则表达式跨越多行，因此您需要使用多个命令来实现您想要的效果，例如类似的东西：

'/(\s*#?)server\s*\{/,/\1\}/d'

但不幸的是，sed不允许以前的正则表达式引用，所以上面的内容都不起作用。

Answer 2

这里有几件事。

首先，默认情况下，sed使用BRE作为其正则表达式格式。您需要在BRE中编写正则表达式，或者需要使用sed选项来告诉它解释ERE。该选项将取决于您尚未作为标记共享的平台，因此请阅读您的man页面以了解要使用的内容。

其次，为了处理多行文本，您需要在编辑缓冲区中包含这些多行。您可以在逐步浏览文件时将它们附加到保留缓冲区，然后立即处理它们。这是非常先进的sed用法，比大多数人都难以处理。即使我们可以将一些有效的东西组合在一起，它也会像线路噪声一样读起来，事后几乎无法支持。

我建议改用awk。

#!/usr/bin/awk -f

# pay attention to are "start of server" line,
/^[[:space:]]*server {/ { n=1 }

# increment bracket counter within the server block,
n>0 && /^[[:space:]]*{/ { n++ }

# decrement the bracket counter within the server block,
n>0 && /^[[:space:]]*}/ { n-- }

# and if we're still within the block, skip to the next line.
n>0 { next }

# short-hand for "print the current line"
1

请注意，条件包含n>0而不仅仅是n，因为awk会将 任何非零值 评估为“true”。

另请注意，这仅适用于每行包含一个squirly括号的文件。我不确定nginx是否需要这个，但如果它允许使用} }关闭一个节内的节，请注意上面的脚本不能正确解析它。

YMMV。未经动物试验。可能含有坚果。

sed从文件中删除代码块

2 个答案: