Most Linux / UNIX configuration files are documented using comments, but some time I just need to see line of configuration text in a file. How can I view just the uncommented configuration file directives from squid.conf or httpd.conf file?
To view just the uncommented lines of text in a config file use the grep, sed, awk, perl or any other text processing utility provided by UNIX / BSD / Linux operating systems.
grep Command Example
GNU/grep command can be used as follows:
$ grep -v "^#" /path/to/config/file
$ grep -v "^#" /etc/apache2/apache2.conf
Sample outputs:
ServerRoot "/etc/apache2" LockFile /var/lock/apache2/accept.lock PidFile ${APACHE_PID_FILE} Timeout 300 KeepAlive On MaxKeepAliveRequests 100 KeepAliveTimeout 15 <IfModule mpm_prefork_module> StartServers 5 MinSpareServers 5 MaxSpareServers 10 MaxClients 150 MaxRequestsPerChild 0 </IfModule> <IfModule mpm_worker_module> StartServers 2 MinSpareThreads 25 MaxSpareThreads 75 ThreadLimit 64 ThreadsPerChild 25 MaxClients 150 MaxRequestsPerChild 0 </IfModule> <IfModule mpm_event_module> StartServers 2 MaxClients 150 MinSpareThreads 25 MaxSpareThreads 75 ThreadLimit 64 ThreadsPerChild 25 MaxRequestsPerChild 0 </IfModule> User ${APACHE_RUN_USER} Group ${APACHE_RUN_GROUP} AccessFileName .htaccess <Files ~ "^\.ht"> Order allow,deny Deny from all Satisfy all </Files> DefaultType text/plain HostnameLookups Off ErrorLog /var/log/apache2/error.log LogLevel warn Include /etc/apache2/mods-enabled/*.load Include /etc/apache2/mods-enabled/*.conf Include /etc/apache2/httpd.conf Include /etc/apache2/ports.conf LogFormat "%v:%p %h %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" vhost_combined LogFormat "%h %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" combined LogFormat "%h %l %u %t \"%r\" %>s %O" common LogFormat "%{Referer}i -> %U" referer LogFormat "%{User-agent}i" agent CustomLog /var/log/apache2/other_vhosts_access.log vhost_combined Include /etc/apache2/conf.d/ Include /etc/apache2/sites-enabled/
To suppress blank lines, enter:
egrep -v "^#|^$" /etc/apache2/apache2.conf
sed Command example
GNU / sed command can be used as follows:
$ sed '/ *#/d; /^ *$/d' /path/to/file
$ sed '/ *#/d; /^ *$/d' /etc/apache2/apache2.conf
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{ 6 comments… read them below or add one }
Thats a trick I’ve been using for years, but have came up with a better way to do it than you:
egrep -v ‘^#|^$’ /etc/httpd/conf/httpd.conf
Your sed line does the exact same thing in removing empty lines. Egrep is more concise.
# egrep -v ‘^#|^$’ dovecot.conf
-su: ^$’: command not found
not quite foolproof :)
Same trick here but with cat -s
grep -v “^#” httpd.conf | cat -s
Indeed, jeff has demonstrated a better way.
@sss: Clearly… you aren’t typing the command the same as I did. Why? Because the pipe is being interpreted by the shell and is trying to run it. That tells me that you didn’t actually put it in the single quotes aka ‘ ‘ like your command says. If you did, the shell would not be able to interpret it. Well unless your shell is something really really buggy and I don’t think thats the case as too much would break.
Wow, Jeff coming back literally years later to correct sss, hah
hi, is there a table comparing the syntax between regex in sed and grep? Otherwise could you help me to write in sed the command, check a string, that it should contains cafe, it should have no more then 6 alpha characters and not 3 immediate repeating of the number, or char like cafewaterloo, is ok, caffe111waterloo is not allowed, but cafe 101 waterloo is ok for example