Bash script with .env file and commands

21 February 2025 | Updated on 22 February 2025

Create a bash script which loads and environment variables via an .env file and allows you to call different sub commands via functions.

Goal

Often times you need a small cli script to run commands for a project. Of course there are many special tools to do this kind of thing. But you can always use a simple bash shell script in case you do not want to install another program and add one more dependency to your project.

Example

Create the bash script file

in root of your project git repo

touch ctl.sh
chmod +x ctl.sh

this allows you to call the file as script directly
only add it to your git repo after changing chmod +x.

Edit the bash file

#!/usr/bin/env bash

# check if .env file exists
FILE=".env"
if [ -f "$FILE" ]; then
  echo "Found file: '${FILE}'. Will configure environment variables."
  set -o allexport; source .env; set +o allexport

# uncomment this in case you want to exit in case not .env file was found
# else
#   ###  Control will jump here if $FILE does NOT exists ###
#   echo -e "Error: ${FILE} not found. Can not continue.\ncreate some .env file with environment variables next to this bash file ctl.sh\nIn case you do not use any env just copy .env.sample or create a file .env with NOTUSED=1234"
#   exit 1
fi

set -eo pipefail

# ./ctl.sh hi <name>
function hi {
  NAME="$1"
  if [ -z "$1" ]; then
    echo "No argument supplied"
    exit
  fi
  echo "Hello $NAME :)"
}

# ./ctl.sh hugo:dev (start hugo development server)
function hugo:dev {
  hugo server --disableFastRender --cleanDestinationDir --printPathWarnings -D
}

# ./ctl.sh hugo:build (build hugo website for production)
function hugo:build {
  hugo --minify --cleanDestinationDir --printPathWarnings
}

function help {
  printf "%s <task> [args]\n\nTasks:\n" "${0}"

  # sometimes compgen is not available. then you just will not get a list of available commands.
  compgen -A function | grep -v "^_" | cat -n

  printf "\nExtended help:\n  Each task has comments for general usage\n"
}

TIMEFORMAT=$'\nTask completed in %3lR'
time "${@:-help}"

Use the script

Run command with argument

after the function name you can enter arguments (see function hi)

./ctl.sh run:hi Julius

Structure groups of commands with colon (:) punctuation mark

sometimes I group group functions like this

./ctl.sh hugo:dev
./ctl.sh hugo:build

Configure environment variables

you can set environment variables inside an .env file

TEST_VAR="This is a test value"
# TEST_VAR_2="hashtags are comments. so this variable will be ignored"

configured variables inside the .env file will be avaible when running the ctl.sh script

Additional resources

Configure post url for hugo website AWS organization account switch role