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→INVESTIGATION 2: ADDITIONAL LOOPING STATEMENTS
# Add the following lines in your shell script <u>AFTER</u> the read statement to prompt the user for a mark:<br><span style="font-family:courier;"><br>while ! echo $mark | egrep "^[0-9]{1,}$" > /dev/null 2> /dev/null<br>do<br> read -p "Not a valid number. Enter a mark (0-100): " mark<br>done</span><br><br>
# Save your editing session and exit the text editor (eg. with vi: press '''ESC''', then type ''':wx''' followed by '''ENTER''').<br><br>
# Run your shell script by issuing:<br><span style="color:blue;font-weight:bold;font-family:courier;">./if-5.bash</span>
# When prompted, enter a letter instead of a number. What happens?<br><br>Does the shell script allow you to enter an invalid grade like 200 or -6?<br><br>Let's add an additional error-checking loop to force the user to enter a number between 0 and 100.<br><br>
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