a somewhat supercharged configuration changer/add-er. If someone out there knows something better - please let me know! ;) Seems like this should already exist

setconf.sh

#!/bin/bash
#set-conf bash thing
# for setting a configuration setting in a file defaulting with a : colon assignment
# and adds the setting if it doesn't find it.
#
#setconf <filepath&name> "string" "<setting>" [-y]
#i.e.    setconf.sh /etc/datadog/datadog.yaml "api_key" "your_api_key_here" -y

# Color and formatting definitions
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[0;33m'
LIGHT_BLUE='\033[1;34m'
BLUE='\033[0;34m'
BOLD='\033[1m'
NC='\033[0m' # No Color

function echo_color() {
    local color="$1"
    local message="$2"
    local bold=${3:-false}
    if [ "$bold" = true ]; then
        echo -e "${color}${BOLD}${message}${NC}"
    else
        echo -e "${color}${message}${NC}"
    fi
}

function print_boxed_output() {
    local line1="$1"
    local line2="$2"
    local line3="$3"
    local line4="$4"
    local width=80
    local horizontal_line=$(printf '%*s' "$width" | tr ' ' '-')
    echo -e "${LIGHT_BLUE}+${horizontal_line}+${NC}"
    printf "${LIGHT_BLUE}|${NC} %-76s ${LIGHT_BLUE}|${NC}\n" "$line1"
    printf "${LIGHT_BLUE}|${NC} %-76s ${LIGHT_BLUE}|${NC}\n" "$line2"
    printf "${LIGHT_BLUE}|${NC} %-76s ${LIGHT_BLUE}|${NC}\n" "$line3"
    printf "${LIGHT_BLUE}|${NC} %-76s ${LIGHT_BLUE}|${NC}\n" "$line4"
    echo -e "${LIGHT_BLUE}+${horizontal_line}+${NC}"
}

function spinner() {
    local pid=$1
    local delay=0.1
    local spinstr='|/-\'
    while [ "$(ps a | awk '{print $1}' | grep $pid)" ]; do
        local temp=${spinstr#?}
        printf " [%c]  " "$spinstr"
        local spinstr=$temp${spinstr%"$temp"}
        sleep $delay
        printf "\b\b\b\b\b\b"
    done
    printf "    \b\b\b\b"
}

function detect_separator() {
    local file="$1"
    local colon_count=0
    local equals_count=0

    while IFS= read -r line; do
        # Skip empty lines
        [[ -z "$line" ]] && continue

        # Remove URLs from the line before counting colons
        local line_without_urls=$(echo "$line" | sed -E 's|https?://[^[:space:]]+||g')

        # Count occurrences of : and = with potential surrounding spaces
        colon_count=$((colon_count + $(echo "$line_without_urls" | grep -oE '\s*:\s*' | wc -l)))
        equals_count=$((equals_count + $(echo "$line" | grep -oE '\s*=\s*' | wc -l)))
    done < "$file"

    echo "Colon count (excluding URLs): $colon_count" >&2
    echo "Equals sign count: $equals_count" >&2

    # Determine the more common separator
    if [[ $colon_count -gt $equals_count ]]; then
        echo " : "
    elif [[ $equals_count -gt $colon_count ]]; then
        echo " = "
    else
        # If counts are equal, default to colon
        echo " : "
    fi
}

function create_backup() {
    local file="$1"
    local backup_file="${file}.$(date +%Y%m%d_%H%M%S).bak"
    cp "$file" "$backup_file"
    echo "Backup created: $backup_file"
}

function replace-line-in-file() {
    local file="$1"
    local line_num="$2"
    local setting="$3"
    local settingvalue="$4"
    local separator="$5"
    local non_interactive="$6"
    local replacement="${setting}${separator}${settingvalue}"

    # Get the current line content
    local current_line=$(sed -n "${line_num}p" "$file")
    echo_color $YELLOW "Current value: $current_line" true
    echo_color $GREEN "New value:     $replacement" true

    if [[ "$non_interactive" != "true" ]]; then
        # Prompt for confirmation
        read -p "Do you want to proceed with this change? (y/n): " confirm
        if [[ $confirm != [yY] ]]; then
            echo "Change aborted."
            exit 0
        fi
    fi

    # Create backup
    create_backup "$file"

    # Escape backslash, forward slash and ampersand for use as a sed replacement.
    replacement_escaped=$(echo "$replacement" | sed -e 's/[\/&]/\\&/g')
    sed -i "${line_num}s/.*/${replacement_escaped}/" "$file"
    echo "Change applied successfully."
}

FILENAME="$1"
STRING2CK4="$2"
SETTINGVALUE="$3"
NON_INTERACTIVE="false"

# Check if the last argument is -y
if [[ "${!#}" == "-y" ]]; then
    NON_INTERACTIVE="true"
    # Remove the last argument
    set -- "${@:1:$#-1}"
fi

if [[ -z $FILENAME || -z $STRING2CK4 || -z $SETTINGVALUE ]]; then
    echo "all parameters must be passed!"
    echo "ex."
    echo "setconf.sh <filename & path> <String to search for> <value to set to> [-y]"
    exit 1
fi

#TODO:  test if permission / access to file exists

# Print the first 4 lines in a box
print_boxed_output \
    "Filename: $FILENAME" \
    "STRING2CK4: $STRING2CK4" \
    "SETTINGVALUE: $SETTINGVALUE" \
    "Non-interactive mode: $NON_INTERACTIVE"

# Detect the separator used in the file
echo_color $YELLOW "Notice: Separator detection may take some time for large files." true
echo_color $BLUE "Detecting separators..." false

# Run detect_separator in the background and capture its PID
detect_separator "$FILENAME" > /tmp/separator_result.txt & 
DETECT_PID=$!

# Run the spinner while detect_separator is running
spinner $DETECT_PID

# Read the result from the temporary file
SEPARATOR=$(cat /tmp/separator_result.txt)
rm /tmp/separator_result.txt  # Clean up the temporary file

echo "Detected separator: '$SEPARATOR'"

LINE2RPL=$(grep -n -m 1 "$STRING2CK4" "$FILENAME" | sed 's/\([0-9]*\).*/\1/')

if [ -z "$LINE2RPL" ]; then 
    echo "line2RPL is blank - item not found - prepare to insert at end of file!" 
    echo "New value to be added: ${STRING2CK4}${SEPARATOR}${SETTINGVALUE}"
    
    if [[ "$NON_INTERACTIVE" != "true" ]]; then
        # Prompt for confirmation
        read -p "Do you want to proceed with adding this new line? (y/n): " confirm
        if [[ $confirm != [yY] ]]; then
            echo "Addition aborted."
            exit 0
        fi
    fi

    # Create backup
    create_backup "$FILENAME"

    # Add the new line
    echo "${STRING2CK4}${SEPARATOR}${SETTINGVALUE}" >> "$FILENAME"
    echo "New line added successfully."
else 
    echo "line2RPL is set to '$LINE2RPL' - preparing to replace!"; 
    replace-line-in-file "$FILENAME" "$LINE2RPL" "$STRING2CK4" "$SETTINGVALUE" "$SEPARATOR" "$NON_INTERACTIVE"
fi