How to check if a variable is set in Bash?

How to check if a variable is set in Bash?

bash shell variables

bash

How to trim whitespace from a Bash variable?

string bash variables trim

bash

Set environment variables from file of key/value pairs

bash variables environment-variables

bash

Capturing multiple line output into a Bash variable

bash variables

bash

Length of string in bash

bash variables string-length

bash

Expansion of variables inside single quotes in a command in Bash

bash shell variables quotes

bash

Create timestamp variable in bash script

bash variables timestamp

bash

How to reference a file for variables using Bash?

bash variables configuration-files

bash

What is the difference between ${var}, "$var", and "${var}" in the Bash shell?

bash shell variables syntax

bash

How can I do division with variables in a Linux shell?

linux bash shell variables division

bash

How to split one string into multiple variables in bash shell? [duplicate]

bash shell variables

bash

Dynamic variable names in Bash

bash variables dynamic syntax

bash

How to store standard error in a variable

bash shell redirect variables stderr

bash

Using variables inside a bash heredoc

bash variables sh heredoc

bash

How to remove a newline from a string in Bash

bash variables

bash