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  1. #!/bin/bash
  2.  
  3. checkForVariable() {
  4.     if [[ -z ${!1+set} ]]; then
  5.        echo "Error: Define $1 environment variable"
  6.        # exit 1
  7.     fi
  8. }
  9.  
  10. # var not set
  11. echo "case 1: "
  12. checkForVariable var
  13.  
  14. # var set
  15. echo "case 2: "
  16. var='abcd'
  17. checkForVariable var
  18.  
  19. # var set to empty
  20. echo "case 3: "
  21. var=
  22. checkForVariable var
Success #stdin #stdout 0s 4252KB
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stdin
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Standard input is empty
stdout
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case 1: 
Error: Define var environment variable
case 2: 
case 3:
https://ideone.com/mPIskE
language:
Bash (bash 5.0.3)
created:
5 years ago
visibility:
public

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