How do I use sed to change my configuration files, with flexible keys and values?

Question

I want to search a configuration file for this expression: "central.database". I then want to change the setting associated with "central.database" to "SQLTEST".

The layout of the config file would look like this initially:

central.database = SQLFIRSTTEST 

This is what i want it to look like after the sed replacement:

central.database = SQLTEST 

I am doing this in a bash script, any suggestions, recommendations or alternative solutions are welcome!

(Actually both central.database and SQLTEST come from bash variables here.)

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My current code (third attempt):

sshRetValue=$(ssh -p "35903" -i $HOME/sshids/idrsa-1.old ${1} <<EOF         sed -i "s/^\($CENTRAL_DB_NAME\s*=\s*\).*\$/\1$CENTRAL_DB_VALUE/" /home/testing.txt;         echo $? EOF ) 

Error message:

Pseudo-terminal will not be allocated because stdin is not a terminal. sed: -e expression #1, char 58: unknown option to `s' -bash: line 3: EOF: command not found 

Answer 1

sed -i -e '/central\.database =/ s/= .*/= new_value/' /path/to/file 

Explanation:

• -i tells sed to save the results to the input file. Without it sed will print the results to stdout.
• /central\.database =/ matches lines that contain the string between slashes: central.database =. The . is escaped since it's a special character in regex.
• The s/OLD/NEW/ part performs a substitution. The OLD string is a regular expression to match and the NEW part is the string to substitute in.
• In regular expressions, .* means "match anything". So = .* matches an equal sign, space, and then anything else afterward.