# The problem with source is that it requires the file to have a proper bash syntax, and some special characters will ruin it: =, ", ', <, >, and others. So in some cases you can just
source development.env
# But This version, however, withstands every special character in values:
set -a
source <(cat development.env |
sed -e '/^#/d;/^s*$/d' -e "s/'/'''/g" -e "s/=(.*)/='1'/g")
set +a
# Explanation:
# -a means that every bash variable would become an environment variable
# /^#/d removes comments (strings that start with #)
# /^s*$/d removes empty strings, including whitespace
# "s/'/'''/g" replaces every single quote with ''', which is a trick sequence in bash to produce a quote :)
# "s/=(.*)/='1'/g" converts every a=b into a='b'
# As a result, you are able to use special characters :)
To debug this code, replace source with cat and you'll see what this command produces.