Ensures a specific line stays uncommented in a finalizeSystems block in default.nix

update_finalizeSystems_config.sh

#!/usr/bin/env bash

# This script processes a default.nix file to ensure a specific configuration
# line provided as an argument remains uncommented within a block starting with
# `finalizeSystems [` and ending with `]`, while commenting out other lines
# in the block, and keeps a backup of the original file.

# VERSION=2024-11-20

# Check for the argument
if [ $# -ne 1 ]; then
  echo "Usage: $0 <path-to-config-to-keep-uncommented>"
  exit 1
fi

TARGET_FILE="default.nix"
TARGET_LINE="$1"

# Ensure the file in the argument exists
if [ ! -f "$TARGET_LINE" ]; then
  echo "Error: File '$TARGET_LINE' does not exist. Are you in the right repository?"
  exit 1
fi

# Backup the original file
cp "$TARGET_FILE" "$TARGET_FILE.bak"

# Process the file
awk -v target="$TARGET_LINE" '
/^[ \t]*finalizeSystems[ \t]*\[/ { 
    in_block = 1; 
    print; 
    next 
} 
/^[ \t]*\]/ && in_block { 
    in_block = 0; 
    if (!line_found) { 
        print "    " target; # Add the target line if not found
    } 
    print; 
    next 
} 
in_block {
    if ($0 ~ target) {
        line_found = 1;
        print $0; # Keep the target line uncommented
    } else if (/^[ \t]*#/) {
        print; # Keep already commented lines
    } else {
        print "#" $0; # Comment all other lines
    }
    next
}
{ print } # Print lines outside the block unchanged
' "$TARGET_FILE.bak" > "$TARGET_FILE"

echo "Processed. Original file backed up as $TARGET_FILE.bak"
echo "You may proceed to the next step: 'build'."