mirror of https://github.com/tLDP/LDP
81 lines
1.1 KiB
Bash
81 lines
1.1 KiB
Bash
#!/bin/bash
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echo
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echo "Testing \"0\""
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if [ 0 ] # zero
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then
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echo "0 is true."
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else
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echo "0 is false."
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fi
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echo
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echo "Testing \"NULL\""
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if [ ] # NULL (empty condition)
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then
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echo "NULL is true."
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else
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echo "NULL is false."
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fi
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echo
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echo "Testing \"xyz\""
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if [ xyz ] # string
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then
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echo "Random string is true."
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else
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echo "Random string is false."
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fi
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echo
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echo "Testing \"\$xyz\""
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if [ $xyz ] # Tests if $xyz is null, but...
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# it's only an uninitialized variable.
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then
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echo "Uninitialized variable is true."
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else
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echo "Uninitialized variable is false."
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fi
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echo
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echo "Testing \"-n \$xyz\""
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if [ -n "$xyz" ] # More pedantically correct.
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then
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echo "Uninitialized variable is true."
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else
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echo "Uninitialized variable is false."
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fi
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echo
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# When is "false" true?
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echo "Testing \"false\""
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if [ "false" ]
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then
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echo "\"false\" is true."
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else
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echo "\"false\" is false."
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fi
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echo
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echo "Testing \"\$false\"" # Again, uninitialized variable.
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if [ "$false" ]
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then
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echo "\"\$false\" is true."
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else
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echo "\"\$false\" is false."
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fi
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echo
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exit 0
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