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===Main Objectives of this Practice Tutorial===
:* Use the Explain how to construct '''if-else''' and '''if-elif-else''' control flow statements.
:* Use alternative methods with Explain the purpose of '''forcommand substitution''' loop control flow statement.
:* Use Explain how to issue the '''for''' loop control flow statement using a list with '''command substitution''' with control-flow statements.
:* Configure Explain how to configure and use the '''.bashrc''' start-up file.<br><br>
===Tutorial Reference Material===
| style="padding-left:15px;" |Additional Control Flow Statements/ techniques
* [https://www.tutorialspoint.com/unix/if-else-statement.htm if-else]
* [https://www.tutorialspoint.com/unix/if-else-statement.htm if-elif-else]
* [https://www.cyberciti.biz/faq/bash-for-loop/#:~:text=A%20'for%20loop'%20is%20a,files%20using%20a%20for%20loop. for Loop]
* [https://www.gnu.org/software/bash/manual/html_node/Command-Substitution.html Using Command Substitution]
* [https://bash.cyberciti.biz/guide/While_loop while Loop]<br><br>
===Additional Logic Statements===
<br>
'''if-else statement:'''<br>[[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>
''Example:''
<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>
'''if-elif-else statement:'''[[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>
===Additional Loop Statements===
'''Command Substitution:'''
[[Image:for-command-substitution.png|thumb|right|300px|Example of how a '''for loop with command substitution''' works.]]
<span style="font-family:courier;font-weight:bold">file $(ls)<br>mail -s "message" $(cat email-list.txt) < message.txt<br><br>
'''Using the for Loop with Command Substitution'''
Let’s issue the for loop with a list using command substitution.<br>In the example below, we will use command substitution to issue the ls command and<br>have that output (filenames) become arguments for the for loop.<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>
'''While Loops:'''[[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.''
Take care and good luck in your future endeavours,
<span style="font-size:1.3em; font-family:cursive">Murray Saul</span>
= LINUX PRACTICE QUESTIONS =
