bargsA utility for creating a Bash CLI application.
bargs
A utility for creating a Bash CLI application.
Examples
- Run the example.sh application with Docker
$ docker run --rm -it unfor19/bargs:example --help
- For more examples, take a look at the following repositories
Features
-
Help Message is auto generated, set
bargs > description
to update the usage (--help
) message -
Short and Long Names are supported with
name=person_name
andshort=n
-
Description Per Argument is supported with
description=What is your name?
-
Flexible Assignment enables passing arguments with the equal sign or a whitespace
example.sh --name "Willy Wonka"
example.sh --name="Willy Wonka"
-
Default Value for each argument can be set with
default=some-value
- If
default
contains whitespaces, use double quotes -default="Willy Wonka"
- If
default
starts with a$
, then it's a variable
default=$LANG
is evaluted todefault=en_US.UTF-8
- If
-
Allow Environment Variables with
allow_env_var=true
, if argument is empty then the environment variable will be used. If environment variable is empty, thedefault
will be used- Environment variable name must be UPPERCASED,
export USERNAME=willywonka
- Available in your application as
$USERNAME
or$username
- Environment variable name must be UPPERCASED,
-
Allow Empty Values with
allow_empty=true
-
Flag Argument with
flag=true
, if the flag is provided, its value is true -CI=true
-
Constrain Values is supported with
options=first second last
, use whitespace as a separator -
Prompt for arguments with
prompt=true
- Hide user input with
hidden=true
- Prompt for value confirmation with
confirmation=true
- Hide user input with
Requirements
- Bash v4.4+
- Util-Linux - We're printing beautiful stuff with the column command
macOS
brew install util-linux
Ubuntu (Debian)
sudo apt-get -y update && sudo apt-get install -y bsdmainutils
Alpine
apk add --no-cache util-linux bash
CentOS
yum update -y && yum install -y util-linux bash
Windows
Works in Windows-Subsystem-Linux (WSL) using Ubuntu 18.04
More details - Expand/Collapse
Make sure you use dos2unix on all files, see another example here
choco install dos2unix
# ...
dos2unix bargs.sh bargs_vars example.sh tests.sh
# ...
wsl -u root -d Ubuntu-18.04 -- source example.sh
Getting Started
-
Download
bargs.sh
(10 kilobytes) and thebargs_vars
template- Latest version (master)
curl -sL --remote-name-all bargs.link/{bargs.sh,bargs_vars}
- Specific release (v1.x.x)
curl -sL --remote-name-all bargs.link/1.1.4/{bargs.sh,bargs_vars}
- Latest version (master)
-
Reference to
bargs_vars
- do one of the following- Default behavior -
bargs.sh
andbargs_vars
are in the same folder - Specific
bargs_vars
path -export BARGS_VARS_PATH="${PWD}/path/to/my_bargs_vars"
, see tests.sh
- Default behavior -
-
Edit
bargs_vars
- Declare arguments/variables, here are some ground rules- The delimiter
---
is required once at the beginning, and twice in the end - Characters which are not supported:
=
,~
,\
,'
,"
- The last variable
bargs
is necessary, comments below - It's best to
source
bargs at the top of the bash script. Do not addset -o pipefail
beforesource bargs.sh
- The delimiter
---
name=bargs # DON'T TOUCH!
description=bash example.sh -n Willy --gender male -a 99 # Editable, that's the usage message
default=irrelevant # DON'T TOUCH!
---
---
bargs_vars - Expand/Collpase
---
name=person_name
short=n
description=What is your name?
default="Willy Wonka"
---
name=age
short=a
description=How old are you?
prompt=true
confirmation=true
---
name=gender
short=g
description=male or female?
options=male female
prompt=true
---
name=location
short=l
description=Where do you live?
default="chocolate factory"
---
name=favorite_food
short=f
allow_empty=true
options=chocolate pizza
description=chocolate or pizza?
---
name=secret
short=s
default=!@#%^&*?/.,[]{}+-|
description=special characters
---
name=language
short=lang
default=$LANG
description=default value can be a variable
---
name=password
short=p
prompt=true
hidden=true
confirmation=true
description=What is your password?
---
name=happy
short=hp
flag=true
description=Flag for indicating that you are happy
---
name=ci
short=ci
flag=true
description=Flag for indicating it is a CI/CD process
---
name=username
short=un
allow_env_var=true
description=Username fetched from environment variable
default=willywonka
---
name=bargs
description=bash example.sh -n Willy --gender male -a 99
default=irrelevant
---
---
-
Add one of the following lines at the beginning of your application (see Usage below)
-
bargs.sh
is in the root folder of your project (just like in this repo)source "${PWD}"/"$(dirname ${BASH_SOURCE[0]})"/bargs.sh "$@"
-
bargs.sh
is in a subfolder, for exampletools
source "${PWD}"/"$(dirname ${BASH_SOURCE[0]})"/tools/bargs.sh "$@"
-
-
The arguments are now available as environment variables, both lowercased and UPPERCASED (see Usage below)
Usage
Using the bargs_vars
above in our application - example.sh
#!/bin/bash
source "${PWD}"/"$(dirname ${BASH_SOURCE[0]})"/bargs.sh "$@"
echo "
Name: ~ $person_name
Age: ~ $age
Gender: ~ $gender
Location: ~ $location
Favorite food: ~ $favorite_food
Secret: ~ $secret
Password: ~ $password
OS Language: ~ $language
I am happy: ~ $happy
CI Process: ~ $CI
Uppercased var names: ~ $PERSON_NAME, $AGE years old, from $LOCATION
Username from env var: ~ $username " \
| column -t -s "~"
Usage output
Results after running tests.sh - Expand/Collapse
-------------------------------------------------------
[LOG] Bargs Vars Path - Should pass
[LOG] Executing: source example.sh -a 33 --gender male -p mypassword
[LOG] Output:
Name: Oompa Looma
Age: 33
Gender: male
Location: chocolate factory
Favorite food:
Secret: !@#%^&*?/.,[]{}+-|
Password: mypassword
OS Language: C.UTF-8
I am happy:
CI Process:
Uppercased var names: Oompa Looma, 33 years old, from chocolate factory
Username from env var: runner
[LOG] Test passed as expected
-------------------------------------------------------
[LOG] Help Menu - Should pass
[LOG] Executing: source example.sh -h
[LOG] Output:
Usage: bash example.sh -n Willy --gender male -a 99
--person_name | -n [Willy Wonka] What is your name?
--age | -a [REQUIRED] How old are you?
--gender | -g [REQUIRED] male or female?
--location | -l [chocolate factory] Where do you live?
--favorite_food | -f [] chocolate or pizza?
--secret | -s [!@#%^&*?/.,[]{}+-|] special characters
--language | -lang [C.UTF-8] default value can be a variable
--password | -p [REQUIRED] What is your password?
--happy | -hp [FLAG] Flag for indicating that you are happy
--ci | -ci [FLAG] Flag for indicating it is a CI/CD process
--username | -un [willywonka] Username fetched from environment variable
[LOG] Test passed as expected
-------------------------------------------------------
[LOG] Default Values - Should pass
[LOG] Executing: source example.sh -a 99 --gender=male -p mypassword
[LOG] Output:
Name: Willy Wonka
Age: 99
Gender: male
Location: chocolate factory
Favorite food:
Secret: !@#%^&*?/.,[]{}+-|
Password: mypassword
OS Language: C.UTF-8
I am happy:
CI Process:
Uppercased var names: Willy Wonka, 99 years old, from chocolate factory
Username from env var: runner
[LOG] Test passed as expected
-------------------------------------------------------
[LOG] New Values - Should pass
[LOG] Executing: source example.sh -a 23 --gender male -l=neverland -n meir -p mypassword
[LOG] Output:
Name: meir
Age: 23
Gender: male
Location: neverland
Favorite food:
Secret: !@#%^&*?/.,[]{}+-|
Password: mypassword
OS Language: C.UTF-8
I am happy:
CI Process:
Uppercased var names: meir, 23 years old, from neverland
Username from env var: runner
[LOG] Test passed as expected
-------------------------------------------------------
[LOG] Valid Options - Should pass
[LOG] Executing: source example.sh -a 23 --gender male -l neverland -n meir -f pizza -p=mypassword
[LOG] Output:
Name: meir
Age: 23
Gender: male
Location: neverland
Favorite food: pizza
Secret: !@#%^&*?/.,[]{}+-|
Password: mypassword
OS Language: C.UTF-8
I am happy:
CI Process:
Uppercased var names: meir, 23 years old, from neverland
Username from env var: runner
[LOG] Test passed as expected
-------------------------------------------------------
[LOG] Special Characters - Should pass
[LOG] Executing: source example.sh -a 99 --gender male -s MxTZf+6KHaAQltJWipe1oVRy -p mypassword
[LOG] Output:
Name: Willy Wonka
Age: 99
Gender: male
Location: chocolate factory
Favorite food:
Secret: MxTZf+6KHaAQltJWipe1oVRy
Password: mypassword
OS Language: C.UTF-8
I am happy:
CI Process:
Uppercased var names: Willy Wonka, 99 years old, from chocolate factory
Username from env var: runner
[LOG] Test passed as expected
-------------------------------------------------------
[LOG] Use Flag - Should pass
[LOG] Executing: source example.sh -a 23 --gender male --happy -p mypassword -ci
[LOG] Output:
Name: Willy Wonka
Age: 23
Gender: male
Location: chocolate factory
Favorite food:
Secret: !@#%^&*?/.,[]{}+-|
Password: mypassword
OS Language: C.UTF-8
I am happy: true
CI Process: true
Uppercased var names: Willy Wonka, 23 years old, from chocolate factory
Username from env var: runner
[LOG] Test passed as expected
-------------------------------------------------------
[LOG] Empty Argument - Should fail
[LOG] Executing: source example.sh -a 99 --gender -p mypassword
[LOG] Output:
[HINT] Valid options: male OR female
[ERROR] Invalid value "-p" for the argument "gender"
Usage: bash example.sh -n Willy --gender male -a 99
--person_name | -n [Willy Wonka] What is your name?
--age | -a [REQUIRED] How old are you?
--gender | -g [REQUIRED] male or female?
--location | -l [chocolate factory] Where do you live?
--favorite_food | -f [] chocolate or pizza?
--secret | -s [!@#%^&*?/.,[]{}+-|] special characters
--language | -lang [C.UTF-8] default value can be a variable
--password | -p [REQUIRED] What is your password?
--happy | -hp [FLAG] Flag for indicating that you are happy
--ci | -ci [FLAG] Flag for indicating it is a CI/CD process
--username | -un [willywonka] Username fetched from environment variable
[LOG] Test failed as expected
-------------------------------------------------------
[LOG] Unknown Argument - Should fail
[LOG] Executing: source example.sh -a 99 -u meir -p mypassword
[LOG] Output:
[ERROR] Unknown argument "-u"
Usage: bash example.sh -n Willy --gender male -a 99
--person_name | -n [Willy Wonka] What is your name?
--age | -a [REQUIRED] How old are you?
--gender | -g [REQUIRED] male or female?
--location | -l [chocolate factory] Where do you live?
--favorite_food | -f [] chocolate or pizza?
--secret | -s [!@#%^&*?/.,[]{}+-|] special characters
--language | -lang [C.UTF-8] default value can be a variable
--password | -p [REQUIRED] What is your password?
--happy | -hp [FLAG] Flag for indicating that you are happy
--ci | -ci [FLAG] Flag for indicating it is a CI/CD process
--username | -un [willywonka] Username fetched from environment variable
[LOG] Test failed as expected
-------------------------------------------------------
[LOG] Invalid Options - Should fail
[LOG] Executing: source example.sh -a 23 --gender male -l neverland -n meir -f notgood -p mypassword
[LOG] Output:
[HINT] Valid options: chocolate OR pizza
[ERROR] Invalid value "notgood" for the argument "favorite_food"
Usage: bash example.sh -n Willy --gender male -a 99
--person_name | -n [Willy Wonka] What is your name?
--age | -a [REQUIRED] How old are you?
--gender | -g [REQUIRED] male or female?
--location | -l [chocolate factory] Where do you live?
--favorite_food | -f [] chocolate or pizza?
--secret | -s [!@#%^&*?/.,[]{}+-|] special characters
--language | -lang [C.UTF-8] default value can be a variable
--password | -p [REQUIRED] What is your password?
--happy | -hp [FLAG] Flag for indicating that you are happy
--ci | -ci [FLAG] Flag for indicating it is a CI/CD process
--username | -un [willywonka] Username fetched from environment variable
[LOG] Test failed as expected
-------------------------------------------------------
[LOG] Missing bargs_vars - Should fail
[LOG] Executing: source example.sh -h
[LOG] Output:
[ERROR] Make sure bargs_vars is in the same folder as bargs.sh
Another option - export BARGS_VARS_PATH="/path/to/my_bargs_vars"
[LOG] Test failed as expected
Package your application with Docker
You can use Docker to package your Bash script as a Docker image, see the following example
-
Clone this repository
-
Build the image, see Dockerfile.example, tag it
bargs:example
docker build -f Dockerfile.example -t bargs:example .
-
Run a container that is based on the image above
docker run --rm -it bargs:example -a 23 -g male
Use this repository as a template
Thinking of writing a new Bash script? Hit the Use this template button and get a fully working example of bargs, including GitHub Actions workflows.
Contributing
Report issues/questions/feature requests on the Issues section.
Pull requests are welcome! These are the steps:
- Fork this repo
- Create your feature branch from master (
git checkout -b my-new-feature
) - Add the code of your new feature
- Run tests on your code, feel free to add more tests
bash tests.sh ... # All good? Move on to the next step
- Commit your remarkable changes (
git commit -am 'Added new feature'
) - Push to the branch (
git push --set-up-stream origin my-new-feature
) - Create a new Pull Request and provide details about your changes
Authors
Created and maintained by Meir Gabay
License
This project is licensed under the MIT License - see the LICENSE file for details