how to parse a config file (*.conf) in shell script?

Question

I am new to shell script. I have a file app.conf as :

[MySql]
user = root
password = root123
domain = localhost
database = db_name
port = 3306

[Logs]
level = logging.DEBUG

[Server]
port = 8080

I want to parse this file in shell script and want to extract mysql credentials from the same. How can I achieve that?

Answer 1

I'd do this:

pw=$(awk '/^password/{print $3}' app.conf)

user=$(awk '/^user/{print $3}' app.conf)


echo $pw
root123

echo $user
root

The $() sets the variable pw to the output of the command inside. The command inside looks through your app.conf file for a line starting password and then prints the 3rd field in that line.

EDITED

If you are going to parse a bunch of values out of your config file, I would make a variable for the config file name:

CONFIG=app.conf
pw=$(awk '/^password/{print $3}' "${CONFIG}")
user=$(awk '/^user/{print $3}' "${CONFIG}")

Here's how to do the two different ports... by setting a flag to 1 when you come to the right section and exiting when you find the port.

mport=$(awk '/^\[MySQL\]/{f=1} f==1&&/^port/{print $3;exit}' "${CONFIG}")
sport=$(awk '/^\[Server\]/{f=1} f==1&&/^port/{print $3;exit}' "${CONFIG}")

Answer 2

You will want to search for "shell ini file parser". I would start with something like this:

ini_get () {
    awk -v section="$2" -v variable="$3" '
        $0 == "[" section "]" { in_section = 1; next }
        in_section && $1 == variable {
            $1=""
            $2=""
            sub(/^[[:space:]]+/, "")
            print
            exit 
        }
        in_section && $1 == "" {
            # we are at a blank line without finding the var in the section
            print "not found" > "/dev/stderr"
            exit 1
        }
    ' "$1"
}

mysql_user=$( ini_get app.conf MySql user )