Remove or ignore all comment lines from Linux config files

Suppose that you would like to read a config file without comments. For example we have config.conf file as follows:

# my config.conf file example

# set conf variable to 0

conf = #0;

# end config.conf file

Following grep command assumes that each comment starts with single # character at the beginning of the line. To remove or ignore all comments from a file a following grep command can be used:

$ grep -v ^\# config.conf | grep  .
conf = 0;

NOTE:“grep .” also removes all empty lines from a file.

One reason to ignore all comment lines is to see relevant config settings of any particular conf file. As an example /etc/hdparm.conf contains 137 lines.

$ cat /etc/hdparm.conf | wc -l

when removing comment lines we get:

$ grep -v ^\# /etc/hdparm.conf | grep  .