Question

Which of these is NOT a valid variable in bash?

1) __ (double underscore)
2) _1var (underscore 1 var)
3) _var_ (underscore var underscore)

Answer 1

All the given options (__ , _1var, _var_) are valid variable names in Bash according to the naming conventions where a variable may consist of alphanumeric characters and underscores, beginning with a letter or underscore.

Step-by-step explanation:

In Bash, variable names may consist only of alphanumeric characters and underscores. They must start with either a letter or an underscore. Considering this, let's analyze the given options:

• __ (double underscore) is a valid variable name.
• _1var (underscore 1 var) is a valid variable name.
• _var_ (underscore var underscore) is also a valid variable name.

All of the options presented are valid variable names in Bash. Therefore, there is no incorrect option listed based on Bash's variable naming conventions.