Load environment variables from dotenv / .env file in Bash

load_dotenv.sh

if [ ! -f .env ]
then
  export $(cat .env | xargs)
fi

env $(cat .env)
this does not work for me but this one works

env $(cat .env|xargs) CMD

my .env has some special value such as FOO='VPTO&wH7$^3ZHZX$o$udY4&i'
@NatoBoram

A simple solution that works for bash, zsh, and fish:

eval export $(cat .env)

Use this to create the file

export -p > .env

and just

. .env

to read it back in

From man export:

The shell shall format the output, including the proper use of quoting, so that it is suitable for reinput to the shell as commands that achieve the same exporting results

Although set -a; source .env; set +a is elegant and short, one feature which I missed is this overwrite existing exported variables.
I my use case I have a script, which connects to postgres with a predefined user. This user is stored in .env file as PG_USER=myuser. So the script does the magical set -a; source .env; set +a and everything works. But sometimes I need ad-hoc change the user. So what I'd do is PG_USER=postgres ./my_script.sh. In order not to over write the existing var I did this horrendous piece of code:

IFS=$'\n'
for l in $(cat /etc/my_service/.env); do
    IFS='=' read -ra VARVAL <<< "$l"
    # If variable with such name already exists, preserves it's value
    eval "export ${VARVAL[0]}=\${${VARVAL[0]}:-${VARVAL[1]}}"
done
unset IFS

The cleanest solution I found for this was using allexport and source like this

set -o allexport
source .env set
+o allexport

This was by far the best solution here for me, removed all the complexity around certain chars, spaces comments etc. Just needed a tweak on formatting to prevent others being tripped up, should be:

set -o allexport source .env set +o allexport

work like a charm. ty