20 lines
		
	
	
		
			417 B
		
	
	
	
		
			Plaintext
		
	
	
		
			Executable File
		
	
	
	
	
			
		
		
	
	
			20 lines
		
	
	
		
			417 B
		
	
	
	
		
			Plaintext
		
	
	
		
			Executable File
		
	
	
	
	
# tests of return value inversion
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# placeholder for future expansion
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# user subshells (...) did this wrong in bash versions before 2.04
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! ( echo hello | grep h >/dev/null 2>&1 ); echo $?
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! echo hello | grep h >/dev/null 2>&1 ; echo $?
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! true ; echo $?
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! false; echo $?
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! (false) ; echo $?
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! (true); echo $?
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! true | false ; echo $?
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! false | true ; echo $?
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! (true | false) ; echo $?
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! (false | true) ; echo $?
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