How to check if a variable is set in Bash?

How to check if a variable is set in Bash?

bash shell variables

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Expansion of variables inside single quotes in a command in Bash

bash shell variables quotes

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How to store standard error in a variable

bash shell redirect variables stderr

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

bash shell variables

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

bash shell variables syntax

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

linux bash shell variables division

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How to base64 encode image in linux bash / shell

linux image shell variables base64

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export not working in my shell script

linux shell variables terminal

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How to read output of sed into a variable

shell variables sed

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Increment variable value by 1 (shell programming)

shell debugging variables ubuntu command-line

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POSIX-Compliant Way to Scope Variables to a Function in a Shell Script

function shell variables scope posix

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Differences between declare, typeset and local variable in Bash

bash shell variables scope declare

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Shell Scripting: Using a variable to define a path

bash shell variables path

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Bash: Echoing a echo command with a variable in bash

bash shell variables echo

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Shell variable issue when trying to mkdir

linux bash shell variables

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