UNIX for Dummies Questions & Answers

I am needing to replace a whole line of code in a file with a new line of code. This is what I need to do.

I need to replace.

$db_url = 'mysql://test_dev:test12@localhost/test';

With

$db_url = 'mysql://$dbuser:$dbpass@localhost/$dbase';

OK this is where it gets complicated. The first $db_url = line is not allways going to be set to test_dev:test12 etc... I need to be able to find the $db_url line and replace it with the second line. I hope this makes sence. Its just alot safer if I can replace the whole line.

Yes the $dbuser, $dbpass, $dbase are variables I am using in my script.

So any help would be appretiated.

filmguy

You can try this, it searches for a line with "$db_url =" to do the replacement, the trick is to escape the single quotes correctly:

Code:

sed 's!\$db_url =.*!$db_url = '"'"'mysql://$dbuser:$dbpass@localhost/$dbase'"'"';!' file

Regards

OK so how do I do that??

Code:

sed 's!\$db_url =.*!$db_url = '"'"'mysql://$dbuser:$dbpass@localhost/$dbase'"'"';!' file

I know nothing about sed really so how do I get the above statement to work in redhad es 4 server ?? When I tried it all it did was print the file to the screen. I replaced file with my file name and it printed the file to the screen. No replacement was done in the file.

Filmguy

Redirect the output to another file.
Then do diff to see the difference.

sed prints the result to the screen (standard output).
You can redirect the output to a file and replace the original file with it:

Code:

sed 's!\$db_url =.*!$db_url = '"'"'mysql://$dbuser:$dbpass@localhost/$dbase'"'"';!' orig_file > new_file

If the replacements are correct, replace the original file with the new file:

Code:

mv new_file orig_file

Regards