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Parse a .env (dotenv) file directly using BASH
# Pass the env-vars to MYCOMMAND
eval $(egrep -v '^#' .env | xargs) MYCOMMAND
# … or ...
# Export the vars in .env into your shell:
export $(egrep -v '^#' .env | xargs)
@ko1nksm
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ko1nksm commented Apr 12, 2021

Seeing that this thread has been going on for long years, I figured we need a dotenv tool for the shell.

And I wrote it.
https://github.com/ko1nksm/shdotenv

There is no formal specification for .env, and each is slightly different, but shdotenv supports them and correctly parses comments, whitespace, quotes, etc. It is a single file shell script that requires only awk and runs lightly.

There is no need to waste time on trial and error anymore.

@smac89
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smac89 commented Apr 15, 2021

The following worked well for me in github actions:

eval "cat <<EOF
$(egrep -v '^#' .env)
EOF
" | tee --append $GITHUB_ENV

Tips for using this (things that bit me):

  • Don't quote anything unless absolutely necessary; the quotes will be taken literally
  • Avoid interpolation which uses a variable inside the .env file. So if your file contains FOO and you try to use in in another variable like FOOBAR=${FOO}bar, all you will get is FOOBAR=bar

Apart from these, it supports pretty much anything you can do regularly including using variables that store the output of a command

@adriancuadrado
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adriancuadrado commented Apr 15, 2021

Here is my contribution, which I developed with no idea someone already did something similar (I saw too many comments and I decided to develop it instead of reading all of them):

eval "$(
    cat <(
        grep -vE -e '^\s*#' -e '^\s*$' < .env |
        grep -E "^[A-Z0-9_]+=['\"]"
    ) <(
        grep -vE -e '^\s*#' -e '^\s*$' -e "^[A-Z0-9_]+=['\"]" < .env |
        sed -r "s/^([A-Z0-9_]+=)(.*)/\\1'\\2'/"
    )
)"

Explanation:

  1. Remove all comments and empty lines:
    • Regex for comments: ^\s*#
    • Regex for empty lines: ^\s*$
    • Grep command:
      grep -vE -e '^\s*#' -e '^\s*$' < .env
      
  2. Get all variables that do not need treatment (i.e. those which are already inside quotes):
    grep -E "^[A-Z0-9_]+=['\"]"
    
  3. Pipe step 1 to step 2:
    grep -vE -e '^\s*#' -e '^\s*$' < .env |
    grep -E "^[A-Z0-9_]+=['\"]"
    
  4. Use process substitution to pass the result as a parameter to cat (I could have used a temporal file, but meh):
    <(
        grep -vE -e '^\s*#' -e '^\s*$' < .env |
        grep -E "^[A-Z0-9_]+=['\"]"
    )
    
  5. Get all variables that do need treatment:
    grep -vE -e '^\s*#' -e '^\s*$' -e "^[A-Z0-9_]+=['\"]" < .env
    

    Notice how the 3 regular expressions are the same as in steps 1 and 2. The only difference here is that I reuse the -v option with the third regex.

  6. Put the single quotes to avoid problems with special characters:
    • Regex for the variable with '=': ^([A-Z0-9_]+=)
    • Regex for the rest of the contents that must be inside single quotes: (.*)
    • Put the first group as is and the second between quotes: \\1'\\2'
    • Sed command:
      sed -r "s/^([A-Z0-9_]+=)(.*)/\\1'\\2'/"
      
  7. Pipe step 5 to step 6:
    grep -vE -e '^\s*#' -e '^\s*$' -e "^[A-Z0-9_]+=['\"]" < .env |
    sed -r "s/^([A-Z0-9_]+=)(.*)/\\1'\\2'/"
    
  8. Do pretty much the same as step 4:
    <(
        grep -vE -e '^\s*#' -e '^\s*$' -e "^[A-Z0-9_]+=['\"]" < .env |
        sed -r "s/^([A-Z0-9_]+=)(.*)/\\1'\\2'/"
    )
    
  9. Concat and eval:
eval "$(
    cat <(
        grep -vE -e '^\s*#' -e '^\s*$' < .env |
        grep -E "^[A-Z0-9_]+=['\"]"
    ) <(
        grep -vE -e '^\s*#' -e '^\s*$' -e "^[A-Z0-9_]+=['\"]" < .env |
        sed -r "s/^([A-Z0-9_]+=)(.*)/\\1'\\2'/"
    )
)"

This is basically what @kolypto does here, but more complex and worse because it doesn't take into consideration the variables that contain single or double quotes inside them, because I should have been able to reuse the result of some grep commands and because maybe there is also a way to not have to feed 2 commands with the contents of the same file (I wrote < .env twice). I had some fun coding this at least ;)

@adriancuadrado
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adriancuadrado commented Apr 15, 2021

If you are seeking for an aswer and have scrolled to the bottom to find it, here it is (thanks to @abij. You can see his answer here):

set -o allexport
eval $(cat '.env' | sed -e '/^#/d;/^\s*$/d' -e 's/\(\w*\)[ \t]*=[ \t]*\(.*\)/\1=\2/' -e "s/=['\"]\(.*\)['\"]/=\1/g" -e "s/'/'\\\''/g" -e "s/=\(.*\)/='\1'/g")
eval $(cat '.env.local' | sed -e '/^#/d;/^\s*$/d' -e 's/\(\w*\)[ \t]*=[ \t]*\(.*\)/\1=\2/' -e "s/=['\"]\(.*\)['\"]/=\1/g" -e "s/'/'\\\''/g" -e "s/=\(.*\)/='\1'/g")
set +o allexport

Just make sure you execute that monster in the same folder that you have your .env file.
The second eval is to read the .env.local file, whose variables should override the ones in .env

@mopcweb
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mopcweb commented Apr 19, 2021

TL;DR;

local result=$(grep ^VAR_NAME=.* path/to/.env | cut -d "=" -f 2);

More protected function to get necessary var and throw error if VAR not found, or invalid path provided.

Usage:

local port=`getEnvVar --var PORT --path ./some-project/.env`;
echo "port = $port";

Code

# Throws error - if it is.
#
# @example: exitIfError $? "Your error text".
# @example: exitIfError $1 "Your error text".
function exitIfError() {
  local exit_code=$1
  shift
  [[ $exit_code ]] &&
    ((exit_code != 0)) && {
      echo "ERROR. $@" >&2;
      exit "$exit_code";
    }
}


# Gets ENV property from provided .env file
#
# @param var - Variable name
# @param path - Path to env file.
# @param [file] - Optional fileName param. @default .env.
function getEnvVar() {
  # This line is necessary to parse function named args
  # @see https://gist.github.com/mopcweb/38f5d09525f8defa5aa807d95efa8307
  while [[ $# -gt 0 ]]; do if [[ $1 == *"--"* ]]; then if [[ $2 != *"--"* ]]; then local "${1/--/}"="${2:-true}"; else local "${1/--/}"=true; fi; fi; shift; done;
  [[ -n $file ]] && local fileName=$file || local fileName=".env";

  [[ -z $var || -z $path ]] && exitIfError 1 "getEnvVar: --var & --path are required.";
  [[ ! -d $path ]] && exitIfError 1 "getEnvVar: --path should be a valid dir.";

  local result=$(grep ^$var=.* $path/$fileName | cut -d "=" -f 2);

  [[ -z $result ]] && exitIfError 1 "getEnvVar: there is no such $var var in $path/$fileName file.";

  echo $result;
}

@abij
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abij commented Apr 19, 2021

@mopcweb Can you update with input and output, what is supported in the .env file?
And how much fun did you have, creating your own solution ;)?

# INPUT                     Expected:
'FOO=value'                 FOO='value'
"FOO=#value # comment"      FOO='#value # comment'
"FOO=value   "              FOO='value   '
'FOO='                      FOO=''
'export FOO=value'          export FOO='value'
"FOO=foo bar"               FOO='foo bar'
"FOO=   foo"                FOO='   foo'

Test cases from @ko1nksm: https://github.com/ko1nksm/shdotenv/blob/main/spec/docker_spec.sh.
Note: check his awesome script: https://github.com/ko1nksm/shdotenv !

@lzkill
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lzkill commented May 5, 2021

Why not dotenv-cli?

$ dotenv <command with arguments> 
# or
$ dotenv -e .env.custom <command with arguments>

@loopmode
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loopmode commented May 5, 2021

Because not every system has nodejs on it. And it's good that way.

@geoffjukes
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geoffjukes commented May 11, 2021

One-liner that allows unquoted variables that contain spaces:

OLD_IFS=$IFS; IFS=$'\n'; for x in `grep -v '^#.*' .env`; do export $x; done; IFS=$OLD_IFS

@alex-hladun
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alex-hladun commented May 14, 2021

ead_var() {
VAR=$(grep $1 $2 | xargs)
IFS="=" read -ra VAR <<< "$VAR"
echo ${VAR[1]}
}

MY_VAR=$(read_var MY_VAR .env)

Perfect, thanks

@ChrisGibb
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ChrisGibb commented Jul 22, 2021

What about this

# save the existing environment variables
prevEnv=$(env)

# if the .env file exists, source it
[ -f .env ] && . .env

# re-export all vars from the env so they override what ever was set in .env
for e in $prevEnv
do
    export $e
done

@wieczorek1990
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wieczorek1990 commented Jan 21, 2022

I wrote my own because was using forbidden symbols in envs.

This basically adds apostrophes so that all variables will be treated as strings. This way you can use your Docker env files and source them with source envs.sh

import sys


def main(input_path, postfix='.sh'):
    with open(input_path, 'r') as file_handle:
        lines = file_handle.readlines()
        envs = {}
        for line in lines:
            try:
                parts = line.split('=')
                name = parts[0]
                value = ''.join(parts[1:]).rstrip('\n')
            except ValueError:
                pass
            else:
                envs[name] = value

    output_path = f'{input_path}{postfix}'
    with open(output_path, 'w') as file_handle:
        lines = []
        for name, value in envs.items():
            line = f'{name}=\'{value}\'\n'
            lines.append(line)
        file_handle.writelines(lines)


if __name__ == '__main__':
    # Passes first argument as input path.
    main(sys.argv[1])

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