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===Additional Logic Statements===
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[[Image:if-else.png|thumb|right|300px|Example of how an '''if-else''' statement works.<br>(Image licensed under [https://creativecommons.org/licenses/by-sa/3.0/ cc]]'''if-else Statements'''
Unlike using only an if statement, an if-else statement take '''two different sets of actions'''<br>based on the results of the test condition.<br><br>''How it Works:''<br>When the test condition returns a '''TRUE''' value, then the Linux Commands between<br>'''then''' and '''else''' statements are executed.<br>If the test returns a '''FALSE''' value, then the the Linux Commands between<br>the '''else''' and '''fi''' statements are executed.<br><br>
<span style="font-family:courier;font-weight:bold;">num1=5<br>num2=10<br>if test $num1 –lt $num2<br>then<br> echo “Less Than”<br>else<br>echo “Greater Than or Equal to”<br>fi</span><br><br>
[[Image:if-elif-else.png|thumb|right|300px|Example of how an '''if-elif-else''' statement works.<br>(Image licensed under [https://creativecommons.org/licenses/by-sa/3.0/ cc]]'''if-elif-else Statements'''
The '''elif''' statement can be used to perform additional conditional tests of the previous test condition tests '''FALSE'''. This statement is used to make your logic control-flow statement to be more adaptable.<br><br>''How it Works:''<br>If the test condition returns a '''TRUE''' value, then the Linux Commands between<br>'''then''' and '''else''' statements are executed.<br><br>If the test returns a '''FALSE''' value, then '''a new condition is tested''',<br>and action is taken if the result is '''TRUE''', then the Linux Commands between<br>'''then''' and '''else''' statements are executed. '''Additional elif statements''' can be used if additional conditional testing is required . Eventually, an action will be taken<br>when the final test condition is '''FALSE'''.<br><br>
<span style="font-family:courier;font-weight:bold;">for x in $(ls)<br>do<br> echo “The item is: $x”<br>done</span><br><br>
[[Image:while-loop.png|thumb|right|170px|Example of how a '''while''' loop works.<br>(Image licensed under [https://creativecommons.org/licenses/by-sa/3.0/ cc]]'''Using the while Loop Statement'''
''The '''while''' loop is useful to loop based on the result from a test condition or command result.<br>This type of loop is very useful for '''error-checking'''.<br><br><i>How it Works:</i><br>The condition/expression is evaluated, and if the condition/expression is '''TRUE''',<br>the code within … the block is executed.''