What is a convention for naming a constant in Bash?

Question

In shell scripting, even though I use Java or Python style naming convention, I am still unclear about naming a constant.

Many conventions suggest me to use "capital letter" together with "underscore" for naming a constant eg MY_CONSTANT , PI . But in Bash , this may conflict with environment variables .

So, what is the right naming convention for Bash constants?

Answer 1

Together with the question you are linking, there is another related question in Unix & Linux: Are there naming conventions for variables in shell scripts? .

There you can find a couple of good answers:

Variables that are introduced by the operating system or start up scripts etc. are usually all in CAPITALS , these are called ' envrironment variables'.

To prevent your own variables from conflicting with environment variables, it is a good practice to use lower case .

Together with a Shell Style Guide link, where you can find:

Naming Conventions

Function Names

▶ Lower-case, with underscores to separate words. Separate libraries with ::. Parentheses are required after the function name. The keyword function is optional, but must be used consistently throughout a project.

Variable Names

▶ As for function names.

Constants and Environment Variable Names

▶ All caps, separated with underscores, declared at the top of the file.

There is no suggested convention in man bash , just note the "be careful with uppercase" warning.