Grep lines that do not begin with ‘#’ or ‘;’
Recently, we wanted to modify the squid configuration file, which is really really big!
wc -l /etc/squid/squid.conf 7898 /etc/squid/squid.conf
We wanted to find all active rules that are enabled to modify our proxy server. Out of those ~8K lines less than 20 are actually active configuration, the rest is documentation.
To find all active configuration lines we needed to find all lines that:
- are not empty
- do not start with #
- do not start with ;
To do this we used the following grep command
grep "^[^#;]" /etc/squid/squid.conf
The first ^ refers to the beginning of the line, this way if in a line there is some configuration and after that there is a comment it will not be excluded by mistake. The rest, [^#;] matches any character which is not # or ;.
This is what was actually in my configuration file (out of ~8K lines)
acl SSL_ports port 443 acl Safe_ports port 80 # http acl Safe_ports port 21 # ftp acl Safe_ports port 443 # https acl Safe_ports port 70 # gopher acl Safe_ports port 210 # wais acl Safe_ports port 1025-65535 # unregistered ports acl Safe_ports port 280 # http-mgmt acl Safe_ports port 488 # gss-http acl Safe_ports port 591 # filemaker acl Safe_ports port 777 # multiling http acl CONNECT method CONNECT http_access deny !Safe_ports http_access deny CONNECT !SSL_ports http_access allow localhost manager http_access deny manager http_access allow localhost http_access deny all http_port 3128 coredump_dir /var/spool/squid refresh_pattern ^ftp: 1440 20% 10080 refresh_pattern ^gopher: 1440 0% 1440 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0 refresh_pattern (Release|Packages(.gz)*)$ 0 20% 2880 refresh_pattern . 0 20% 4320
