Cut Apache virtual host block - bash

Question

I'm trying to cut certain virtual host from file which has a lot of them using bash.
Eg. in my script I would like to get virtual host which uses the_one_known2.example.com, but another time the_one_known3.example.com, namely I would like to get some part form apache config file with beforehand known URL (present in ServerName or ServerAlias) which is set in bash script as a parameter.
<VirtualHost *:80 *:${SERVER_PORT}>
ServerName test1.example.com
ServerAlias test2.example.com
ServerAlias the_one_known1.example.com
ServerAlias test3.example.com
</VirtualHost>
<VirtualHost *:80 *:${SERVER_PORT}>
ServerName test4.example.com
ServerAlias the_one_known2.example.com
ServerAlias test5.example.com
ServerAlias test6.example.com
</VirtualHost>
<VirtualHost *:80 *:${SERVER_PORT}>
ServerName the_one_known3.example.com
ServerAlias test7.example.com
ServerAlias test8.example.com
ServerAlias test9.example.com
</VirtualHost>
So I my URL variable would change to eg. the_one_known2.example.com I would get:
<VirtualHost *:80 *:${SERVER_PORT}>
ServerName test4.example.com
ServerAlias the_one_known2.example.com
ServerAlias test5.example.com
ServerAlias test6.example.com
</VirtualHost>
[EDIT]
So far I tried to find first line of a selected virtual host:
url_line=$(grep -n -m 1 "${URL}" ./apache.conf" | sed 's/\([0-9]*\).*/\1/')
vitual_host_start_line="$((app_line-1))" // this is an assumption that Virtual Host starts just one line before the first occurance of URL
echo $vitual_host_line // the place it starts
But I have a problem to find a last line of this virtual host because it is first occurence of </VirtualHost> after vitual_host_start_line

Answer 1

With awk:
awk -v name="the_one_known2.example.com" 'BEGIN{RS=ORS="</VirtualHost>\n"} $0~name{print; exit}' file
I assume the_one_known2.example.com is no substring of another domain in your file.
See: 8 Powerful Awk Built-in Variables – FS, OFS, RS, ORS, NR, NF, FILENAME, FNR

Answer 2

With your shown samples, please try following awk code. Written and tested in GNU awk.
awk -v RS='<VirtualHost[^/]*/' -v ORS="VirtualHost>\n" 'RT~/[[:space:]]+the_one_known2\.example\.com\n/{print RT}' Input_file
Explanation: Simple explanation would be, making RS(record separator) from <VirtualHost till next / occurrence(non-greedy match). Then checking if it has [[:space:]]+the_one_known2\.example\.com\n if yes then print matched value, this will print VirtualHost> at ending of passage since its set as ORS value in program.