Mix It Up

Solve Bash blind spots by embedding other scripting languages into your Bash scripts to get the features you need. Pete shows you solutions for floating-point math, charting, GUIs, and hardware integration.

- By Pete Metcalfe

While Bash has a huge variety of command-line tools that you can integrate into your code, sometimes you can still get stuck. Bash is extremely powerful, but, like all programming languages, it has its weakness. Some typical areas that can be challenging when using Bash include:

• Floating-point math

• Charting

• Graphical user interfaces (GUIS)

• Hardware integration

Command-line utilities can help address many of these topics, such as bc for floating-point math or Zenity [1] for user dialogs. While these tools are extremely useful, they may not give you the functionality or customization that you need. A common approach to solving this issue is to write standalone programs in another language, like Python, and then have your Bash script call that program.

You can also solve Bash limitations by embedding code from another scripting language (e.g., Lua, NodeJS, PHP, Python, or Tcl/Tk) within your Bash script. This method offers the advantage of keeping all the code in one script. In this article, I'll look at solving the issues of floating-point math, charting, GUIs, and hardware integration by embedding other scripting languages into Bash.

How to Embed Other Languages

There are several techniques for embedding other programming languages in Bash. For very small code bits, a string of text can be piped to the other scripting language’s interpreter as follows:

Here, a string of commands are piped to Python. A semicolon is used to separate each command. To return the result to Bash, a Python print statement is used.

Some languages, such as Julia and Python, have command-line options to pass in a string of commands (see Listing 1). Commandline options offer the slight advantage of not using a pipe or an echo statement.