Set environment variables from file of key/value pairs

TL;DR: How do I export a set of key/value pairs from a text file into the shell environment?

For the record, below is the original version of the question, with examples.

I'm writing a script in bash which parses files with 3 variables in a certain folder, this is one of them:

MINIENTREGA_FECHALIMITE="2011-03-31"
MINIENTREGA_FICHEROS="informe.txt programa.c"
MINIENTREGA_DESTINO="./destino/entrega-prac1"

This file is stored in ./conf/prac1

My script minientrega.sh then parses the file using this code:

cat ./conf/$1 | while read line; do export $line
done

But when I execute minientrega.sh prac1 in the command line it doesn't set the environment variables

I also tried using source ./conf/$1 but the same problem still applies

Maybe there is some other way to do this, I just need to use the environment variables of the file I pass as the argument of my script.

44 Answers

12 Next

This might be helpful:

export $(cat .env | xargs) && rails c

Reason why I use this is if I want to test .env stuff in my rails console.

gabrielf came up with a good way to keep the variables local. This solves the potential problem when going from project to project.

env $(cat .env | xargs) rails

I've tested this with bash 3.2.51(1)-release

Update:

To ignore lines that start with #, use this (thanks to Pete's comment):

export $(grep -v '^#' .env | xargs)

And if you want to unset all of the variables defined in the file, use this:

unset $(grep -v '^#' .env | sed -E 's/(.*)=.*/\1/' | xargs)

Update:

To also handle values with spaces, use:

export $(grep -v '^#' .env | xargs -d '\n')

on GNU systems -- or:

export $(grep -v '^#' .env | xargs -0)

on BSD systems.

From this answer you can auto-detect the OS with this:

export-env.sh

#!/bin/sh
## Usage:
## . ./export-env.sh ; $COMMAND
## . ./export-env.sh ; echo ${MINIENTREGA_FECHALIMITE}
unamestr=$(uname)
if [ "$unamestr" = 'Linux' ]; then export $(grep -v '^#' .env | xargs -d '\n')
elif [ "$unamestr" = 'FreeBSD' ]; then export $(grep -v '^#' .env | xargs -0)
fi

-o allexport enables all following variable definitions to be exported. +o allexport disables this feature.

set -o allexport
source conf-file
set +o allexport

Problem with your approach is the export in the while loop is happening in a sub shell, and those variable will not be available in current shell (parent shell of while loop).

Add export command in the file itself:

export MINIENTREGA_FECHALIMITE="2011-03-31"
export MINIENTREGA_FICHEROS="informe.txt programa.c"
export MINIENTREGA_DESTINO="./destino/entrega-prac1"

Then you need to source in the file in current shell using:

. ./conf/prac1

source ./conf/prac1

set -a
. ./env.txt
set +a

If env.txt is like:

VAR1=1
VAR2=2
VAR3=3
...

Explanations -a is equivalent to allexport. In other words, every variable assignment in the shell is exported into the environment (to be used by multiple child processes). More information can be found in the Set builtin documentation:

-a Each variable or function that is created or modified is given the export attribute and marked for export to the environment of subsequent commands.

Using ‘+’ rather than ‘-’ causes these options to be turned off. The options can also be used upon invocation of the shell. The current set of options may be found in $-.

I found the most efficient way is:

export $(xargs < .env)

Explanation

When we have a .env file like this:

key=val
foo=bar

run xargs < .env will get key=val foo=bar

so we will get an export key=val foo=bar and it's exactly what we need!

Limitation

It doesn't handle cases where the values have spaces in them. Commands such as env produce this format. – @Shardj

The allexport option is mentioned in a couple of other answers here, for which set -a is the shortcut. Sourcing the .env really is better than looping over lines and exporting because it allows for comments, blank lines, and even environment variables generated by commands. My .bashrc includes the following:

# .env loading in the shell
dotenv () { set -a [ -f .env ] && . .env set +a
}
# Run dotenv on login
dotenv
# Run dotenv on every new directory
cd () { builtin cd $@ dotenv
}

eval $(cat .env | sed 's/^/export /')

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

and it will work.

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.

Here is another sed solution, which does not run eval or require ruby:

source <(sed -E -n 's/[^#]+/export &/ p' ~/.env)

This adds export, keeping comments on lines starting with a comment.

.env contents

A=1
#B=2

sample run

$ sed -E -n 's/[^#]+/export &/ p' ~/.env
export A=1
#export B=2

I found this especially useful when constructing such a file for loading in a systemd unit file, with EnvironmentFile.

I have upvoted user4040650's answer because it's both simple, and it allows comments in the file (i.e. lines starting with #), which is highly desirable for me, as comments explaining the variables can be added. Just rewriting in the context of the original question.

If the script is callled as indicated: minientrega.sh prac1, then minientrega.sh could have:

set -a # export all variables created next
source $1
set +a # stop exporting
# test that it works
echo "Ficheros: $MINIENTREGA_FICHEROS"

The following was extracted from the set documentation:

This builtin is so complicated that it deserves its own section. set allows you to change the values of shell options and set the positional parameters, or to display the names and values of shell variables.

set [--abefhkmnptuvxBCEHPT] [-o option-name] [argument …] set [+abefhkmnptuvxBCEHPT] [+o option-name] [argument …]

If no options or arguments are supplied, set displays the names and values of all shell variables and functions, sorted according to the current locale, in a format that may be reused as input for setting or resetting the currently-set variables. Read-only variables cannot be reset. In POSIX mode, only shell variables are listed.

When options are supplied, they set or unset shell attributes. Options, if specified, have the following meanings:

-a Each variable or function that is created or modified is given the export attribute and marked for export to the environment of subsequent commands.

And this as well:

Using ‘+’ rather than ‘-’ causes these options to be turned off. The options can also be used upon invocation of the shell. The current set of options may be found in $-.

Not exactly sure why, or what I missed, but after running trough most of the answers and failing. I realized that with this .env file:

MY_VAR="hello there!"
MY_OTHER_VAR=123

I could simply do this:

source .env
echo $MY_VAR

Outputs: Hello there!

Seems to work just fine in Ubuntu linux.

Improving on Silas Paul's answer

exporting the variables on a subshell makes them local to the command.

(export $(cat .env | xargs) && rails c)

SAVE=$(set +o | grep allexport) && set -o allexport && . .env; eval "$SAVE"

This will save/restore your original options, whatever they may be.

Using set -o allexport has the advantage of properly skipping comments without a regex.

set +o by itself outputs all your current options in a format that bash can later execute. Also handy: set -o by itself, outputs all your current options in human-friendly format.

The shortest way I found:

Your .env file:

VARIABLE_NAME="A_VALUE"

Then just

. ./.env && echo ${VARIABLE_NAME}

Bonus: Because it's a short one-liner, it's very useful in package.json file

 "scripts": { "echo:variable": ". ./.env && echo ${VARIABLE_NAME}" }

Here's my variant:

 with_env() { (set -a && . ./.env && "$@") }

compared with the previous solutions:

it does not leak variables outside scope (values from .env are not exposed to caller)
does not clobber set options
returns exit code of the executed command
uses posix compatible set -a
uses . instead of source to avoid bashism
command is not invoked if .env loading fails

with_env rails console

If env supports the -S option one may use newlines or escape characters like \n or \t (see env):

env -S "$(cat .env)" command

.env file example:

KEY="value with space\nnewline\ttab\tand
multiple
lines"

Test:

env -S "$(cat .env)" sh -c 'echo "$KEY"'

Simpler:

grab the content of the file
remove any blank lines (just incase you separated some stuff)
remove any comments (just incase you added some...)
add export to all the lines
eval the whole thing

eval $(cat .env | sed -e /^$/d -e /^#/d -e 's/^/export /')

Another option (you don't have to run eval (thanks to @Jaydeep)):

export $(cat .env | sed -e /^$/d -e /^#/d | xargs)

Lastly, if you want to make your life REALLY easy, add this to your ~/.bash_profile:

function source_envfile() { export $(cat $1 | sed -e /^$/d -e /^#/d | xargs); }

(MAKE SURE YOU RELOAD YOUR BASH SETTINGS!!! source ~/.bash_profile or.. just make a new tab/window and problem solved) you call it like this: source_envfile .env

I work with docker-compose and .env files on Mac, and wanted to import the .env into my bash shell (for testing), and the "best" answer here was tripping up on the following variable:

.env

NODE_ARGS=--expose-gc --max_old_space_size=2048

Solution

So I ended up using eval, and wrapping my env var defs in single quotes.

eval $(grep -v -e '^#' .env | xargs -I {} echo export \'{}\')

Bash Version

$ /bin/bash --version
GNU bash, version 3.2.57(1)-release (x86_64-apple-darwin18)
Copyright (C) 2007 Free Software Foundation, Inc.

You can use your original script to set the variables, but you need to call it the following way (with stand-alone dot):

. ./minientrega.sh

Also there might be an issue with cat | while read approach. I would recommend to use the approach while read line; do .... done < $FILE.

Here is a working example:

> cat test.conf
VARIABLE_TMP1=some_value
> cat run_test.sh
#/bin/bash
while read line; do export "$line";
done < test.conf
echo "done"
> . ./run_test.sh
done
> echo $VARIABLE_TMP1
some_value

t=$(mktemp) && export -p > "$t" && set -a && . ./.env && set +a && . "$t" && rm "$t" && unset t

How it works

Create temp file.
Write all current environment variables values to the temp file.
Enable exporting of all declared variables in the sources script to the environment.
Read .env file. All variables will be exported into current environment.
Disable exporting of all declared variables in the sources script to the environment.
Read the contents of the temp file. Every line would have declare -x VAR="val" that would export each of the variables into environment.
Remove temp file.
Unset the variable holding temp file name.

Features

Preserves values of the variables already set in the environment
.env can have comments
.env can have empty lines
.env does not require special header or footer like in the other answers (set -a and set +a)
.env does not require to have export for every value
one-liner

Building on other answers, here is a way to export only a subset of lines in a file, including values with spaces like PREFIX_ONE="a word":

set -a
. <(grep '^[ ]*PREFIX_' conf-file)
set +a

Use shdotenv

dotenv support for shell and POSIX-compliant .env syntax specification

eval "$(shdotenv)"

Usage

Usage: shdotenv [OPTION]... [--] [COMMAND [ARG]...] -d, --dialect DIALECT Specify the .env dialect [default: posix] (posix, ruby, node, python, php, go, rust, docker) -s, --shell SHELL Output in the specified shell format [default: posix] (posix, fish) -e, --env ENV_PATH Location of the .env file [default: .env] Multiple -e options are allowed -o, --overload Overload predefined environment variables -n, --noexport Do not export keys without export prefix -g, --grep PATTERN Output only those that match the regexp pattern -k, --keyonly Output only variable names -q, --quiet Suppress all output -v, --version Show the version and exit -h, --help Show this message and exit

Requirements

shdotenv is a single file shell script with embedded awk script.

POSIX shell (dash, bash, ksh, zsh, etc)
awk (gawk, nawk, mawk, busybox awk)

My .env:

#!/bin/bash
set -a # export all variables
#comments as usual, this is a bash script
USER=foo
PASS=bar
set +a #stop exporting variables

Invoking:

source .env; echo $USER; echo $PASS

Reference

My requirements were:

simple .env file without export prefixes (for compatibility with dotenv)
supporting values in quotes: TEXT="alpha bravo charlie"
supporting comments prefixed with # and empty lines
universal for both mac/BSD and linux/GNU

Full working version compiled from the answers above:

 set -o allexport eval $(grep -v '^#' .env | sed 's/^/export /') set +o allexport

My version :

I print the file, remove commented lines, emptylines, and I split key/value from "=" sign. Then I just apply the export command.

The advantage of this solution is the file can contain special chars in values, like pipes, html tags, etc., and the value doesn't have to be surrounded by quotes, like a real properties file.

# Single line version
cat myenvfile.properties | grep -v '^#' | grep '=' | while read line; do IFS=\= read k v <<< $line; export $k="$v"; done
# Mutliline version:
cat myenvfile.properties | grep -v '^#' | grep '=' | while read line; do IFS=\= read k v <<< $line export $k="$v"
done

I have issues with the earlier suggested solutions:

@anubhava's solution makes writing bash friendly configuration files very annoying very fast, and also - you may not want to always export your configuration.
@Silas Paul solution breaks when you have variables that have spaces or other characters that work well in quoted values, but $() makes a mess out of.

Here is my solution, which is still pretty terrible IMO - and doesn't solve the "export only to one child" problem addressed by Silas (though you can probably run it in a sub-shell to limit the scope):

source .conf-file
export $(cut -d= -f1 < .conf-file)

Modified from @Dan Kowalczyk

I put this in ~/.bashrc.

set -a
. ./.env >/dev/null 2>&1
set +a

Cross-compatible very well with Oh-my-Zsh's dotenv plugin. (There is Oh-my-bash, but it doesn't have dotenv plugin.)

I use this:

source <(cat .env \ | sed -E '/^\s*#.*/d' \ | tr '\n' '\000' \ | sed -z -E 's/^([^=]+)=(.*)/\1\x0\2/g' \ | xargs -0 -n2 bash -c 'printf "export %s=%q;\n" "${@}"' /dev/null)

First Removing comments:

sed -E '/^\s*#.*/d'

Then converting to null delimiters instead of newline:

tr '\n' '\000'

Then replacing equal with null:

sed -z -E 's/^([^=]+)=(.*)/\1\x0\2/g'

Then printing pairs to valid quoted bash exports (using bash printf for %q):

xargs -0 -n2 bash -c 'printf "export %s=%q;\n" "${@}"' /dev/null

Then finally sourcing all of that.

It should work for just about all cases with all special characters.

First, create an environment file that will have all the key-value pair of the environments like below and named it whatever you like in my case its env_var.env

MINIENTREGA_FECHALIMITE="2011-03-31"
MINIENTREGA_FICHEROS="informe.txt programa.c"
MINIENTREGA_DESTINO="./destino/entrega-prac1"

Then create a script that will export all the environment variables for the python environment like below and name it like export_env.sh

#!/usr/bin/env bash
ENV_FILE="$1"
CMD=${@:2}
set -o allexport
source $ENV_FILE
set +o allexport
$CMD

This script will take the first argument as the environment file then export all the environment variable in that file and then run the command after that.

USAGE:

./export_env.sh env_var.env python app.py

sh -ac '. conf-file; yourcommand'

The -a switch exports all variables, so that they are available to the program.

Unlike the longer version set -a; . conf-file; set +a; yourcommandusing sh ensures the exported values are not permanently polluting the current environment. It sources and exports the variables just for the program run in a subshell.

12 Next

Velvet Star Monitor

Set environment variables from file of key/value pairs

44 Answers

Explanation

Limitation

.env contents

sample run

Solution

Use shdotenv

Usage

Requirements

Your Answer

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