How can I delete multiple lines in a config file after a certain section header?

If you want to use `sed`, you'll need to specify the range based on the section header. Here's a basic script you might start with:

```bash
sed '/[database]/,/^[/ { /[database]/!d }' yourfile.ini > output.ini
```

This command will delete everything between the `[database]` line and the next section header. Just make sure to adjust it if there's a different section above `[database]` that you want to keep intact.

If your INI files vary a lot, consider using `crudini`, which is tailored for this kind of task. Here’s how you could loop through and delete keys in a section:

```bash
for key in $(crudini --get yourfile.ini database 2>/dev/null); do
crudini --del yourfile.ini database "$key";
done
```

This will delete all keys under the `[database]` section while keeping the header intact. It's neat and works well for dynamic INI structures.

You can use `awk` for this task quite easily. It allows you to specify the section and skip all the lines after it. Here's a sample command you can try:

```bash
awk -vRS= -vsection=database '$0 ~ "(^|n)[" section "]" {print nl "[" section "]"; nl="n"; next} {print nl $0; nl="n"}' yourfile.ini > output.ini
```

This way, you're effectively looking for the section you want and printing only its header while ignoring the rest. This command assumes blank lines separate your sections. If they aren't, you might need a different approach. Let me know if that helps!

Using Perl can also be a breeze for this. Here's a one-liner that captures the `[database]` header but removes everything else:

```bash
perl -pe 's/
([database])[wW]*?(nn|$)/$1$2/g' yourfile.ini > output.ini
```

This one-liner reads the whole file at once and uses regex to match the desired pattern. Just ensure to test it out on a backup of your file first!

You could also try a simpler `awk` command that checks for lines starting with brackets:

```bash
awk '{ if ($0 ~ /^[database]/) { print; print(""); silent = 1; next; } if ($0 ~ /^
/) silent = 0; if (!silent) print; }' yourfile.ini > output.ini
```

This checks each line, prints the header, adds a blank line, and then stops printing subsequent lines. Give it a shot!