If in your bash script, you want to know if a variable is set or not you can make use of the following,
- The isset function.
- Usiing the -z option
Let's take a look at each of them with examples.
Example 1: The isset function
#!/bin/bash
isset() {
[[ -n "${!1}" ]]
}
my_var="Hey there!"
if isset "my_var"; then
echo "The variable is set."
else
echo "The variable is not set."
fi
Example 2: Using the -z Option
#!/bin/bash
if [ -z "$no" ]; then
echo "The variable is not set."
else
echo "The variable is set."
fi
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