devoalda.gitlab.io/content/en/posts/nbs.md

author	authorEmoji	title	date	description	draft	hideToc	enableToc	enableTocContent	tocPosition	tocLevels	tags	series	categories	image
Devoalda	🐺	Bash - New Bash Script	2020-07-07T10:12:26+08:00	Automate Bash Script Creation	false	false	true	true	inner	h1 h2 h3	bash script automation linux	Bash	bash script automation	images/postImages/Bash_256x256.png

Introduction

This is a simple bash script creation automation script. The script "nbs" is an acronym for "new bash script", which allows for easy automation while creating other bash scripts with a command: nbs newscript.sh.

Why?

In my work flow, the creation of bash script for my system usually contains a few steps, mainly:

• Checking if script exists
  • Edit the existing script OR
  • Create a new script
• Typing out long commands to make a new script
  • vim $HOME/.local/bin/script
• Adding shebang
  • #!/bin/bash
• Making the script executable
  • chmod +x $HOME/.local/bin/script
• Adding a short description of the code

A bash script would be able to automate these steps by using a single command.

Code

Introduction

This scripts assumes that you have a linux file structure. There will be 2 files: bash_template and nbs, both stored in $HOME/.local/share/template/ and $HOME/.local/bin/ respectively.

Template

Create the folder, this is where we will store the templates for new scripts

mkdir $HOME/.local/share/template

Create and edit a new template

vim $HOME/.local/share/template/bash_template

#!/bin/bash

# Done By: Devoalda
# Comment

This is my template for creating new bash scripts. It contains the shebang, author details and a comment section to allow for a short description of the script.

{{< alert theme="info" dir="ltr" >}} Notice the empty line 5, this allows me to start scripting immediately with vim with a keybinding G + i {{< /alert >}}

Script

Create and edit the script

vim $HOME/.local/bin/nbs

You can copy the template to the new script

#!/bin/bash

# Done By: Devoalda
# Comment

The first line of this script will check for the name of the newly created script as an argument.

# Get Filename
[ -z "$1" ] && echo "Error: Please Give a filename!" && exit 1 || filename="$HOME/.local/bin/$1"

{{< alert theme="info" dir="ltr" >}} This is a 1 liner, which checks for filename {{< /alert >}}

The next line will allow for editing the file, if the file exists

# Edit File if File exists
[  -f $filename ] && nvim $filename 

{{< alert theme="info" dir="ltr" >}} This is also a 1 liner, which checks for existance of file. Read more about conditional tags [here]({{< ref "/posts/bash_cheatsheet.md#conditions" >}}) {{< /alert >}}

The last line will create a new file - Copy the template, make the file executable and edit the new file

# Create File if file does not exist
[ ! -f $filename ] && touch $filename && chmod +x $filename && cp $HOME/.local/share/template/bash_template $filename && nvim $filename

Summary

In 3 lines, this script is able to do conditional checking, copying of template and editing the script. This shows the ability of bash scripts. The full code will be listed below, do check it out if you have problems.

With this script, you will be able to create a new bash script from your terminal

$ nbs newscript

{{< tabs nbs bash_template >}} {{< tab >}}

nbs

#!/bin/bash
# Create New Bash Script with template

# Get Filename
[ -z "$1" ] && echo "Error: Please Give a filename!" && exit 1 || filename="$HOME/.local/bin/$1"

# Edit File if File exists
[  -f $filename ] && nvim $filename 

# Create File if file does not exist
[ ! -f $filename ] && touch $filename && chmod +x $filename && cp $HOME/.local/share/template/bash_template $filename && nvim $filename

{{< /tab >}} {{< tab >}}

bash_template

#!/bin/bash

# Done By: Devoalda
# Comment

{{< /tab >}} {{< /tabs >}}

Fixing Errors

$PATH

Ensure that $HOME/.local/bin/ is in your $PATH. If unsure, add the following lines to your ~/.bashrc or ~/.zshrc

# Adds `~/.local/bin` and containing folders to $PATH
export PATH="$PATH:$(du "$HOME/.local/bin/" | cut -f2 | paste -sd ':')"
for file in $HOME/.local/bin/; do
	if [ -d "$file" ]; then
		export PATH="$PATH:$file"
	fi
done

This recursively adds $HOME/.local/bin and containing folders to $PATH.

Permissions

Ensure that nbs is executable

$ chmod +x $HOME/.local/bin/nbs

Script Improvements

There are certain improvements that may allow the script to be modular. For example, in the script nbs, there could be a configuration section which allows users to configure the script path, template path or default editor.

This is how the script could look like after improvements

#!/bin/bash
# Create New Bash Script with template

##############################
# Configurations             #
##############################
EDITOR=${EDITOR-nano}	# Editor is defined in .bashrc/.zshrc or use nano
SCRIPT_PATH=$HOME/.local/bin/
TEMPLATE=$HOME/.local/share/template/bash_template

# Get Filename
[ -z "$1" ] && echo "Error: Please Give a filename!" && exit 1 || filename="$SCRIPT_PATH$1"

# Edit File if File exists
[  -f $filename ] && $EDITOR $filename 

# Create File if file does not exist
[ ! -f $filename ] && touch $filename && chmod +x $filename && cp $TEMPLATE $filename && $EDITOR $filename

You could make further modifications for your use cases or use the same format to automate the creations of scripts for other languages.