Simple script to update variables in a file. Use with variables files where the pattern is key=value.

update-file-variables.sh

#!/usr/bin/env bash

var_file_location="/usr/local/etc/php/php.ini"

declare -A values

values["upload_max_filesize"]="2M"

for key in "${!values[@]}"
do
    grep -q "^$key" $var_file_location && \
        sed -i "s/^\($key\).*/\1=$(eval echo \${values[$key]})/" $var_file_location || \
        echo "$key=${values[$key]}" >> $var_file_location
done