How can I efficiently delete a section of text in a file that matches a regex pattern?

Here's a simple solution using gawk, which makes this pretty clear:

```awk
function process_section() {
if (!skip_section && section) {
printf section
}
section = ""
skip_section = 0
}
BEGIN {
skip_section = 0
section = ""
}
/^[.*]$/ {
process_section()
section = $0 "n"
next
}
/Name=alicew/ {
skip_section = 1
}
{
section = section $0 "n"
}
END {
process_section()
}
```
Just run this script with your input file, and it will filter out the block containing the unwanted line.

If you're comfortable with sed, you can achieve this by storing sections in the hold space and then selectively printing them. Here’s a more straightforward sed script:

```bash
sed -n '
/^$/{ x; p; b } /
^Name=alicew$/ { :loop; n; /^$/{ h; b }; $ q; b loop; }
1{ h; b }
H; ${ g; p }'
```
This might be a bit convoluted, but it works by processing the blocks and ignoring the target block.

You could use a single regex in Perl to do this cleanup. Here’s a command that works:

```bash
perl -p -0 -e 's/((?!nn)[wW])*Name=alicew((?!nn)[wW]*)//g' file
```
This will replace the section with whatever matches the pattern. You can add the `-i` flag for in-place modification if you want.

You can use AWK with the paragraph mode setting to handle this quite easily. Here's a command to achieve that:

```bash
awk -vRS= -vORS='nn' -vNEEDLE='Name=alicew' '!match($0, NEEDLE)' file
```
This will remove any block of text that contains that specific line. Just a heads up, it will add two newlines at the end of the output, but it gets the job done efficiently.

If you're dealing with INI or similar file formats, using a command like this in awk could help:

```bash
awk 'BEGIN { RS=""; FS="n"; ORS="nn" } /Name=alicew/ { next } { print }' in.txt
```
This will skip any section containing 'Name=alicew' and print all the others. If it's a TOML file, tools like dasel might be worth looking into.