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Tutorial12: Shell Scripting - Part 2

32 bytes added, 08:22, 18 March 2021

→‎INVESTIGATION 2: ADDITIONAL LOOPING STATEMENTS

# Run your shell script by issuing: ./for-5.bash

# When prompted, enter a '''letter''' instead of a ''number''. What happens? Does the shell script allow you to enter an invalid grade like '''200''' or '''-6'''? Let's add an additional error-checking loop to force the user to enter a number between 0 and 100.

# Use a text editor like vi or nano to edit the text file called '''~~for~~if-5.bash''' (eg. vi ~~for~~if-5.bash) # Add the following lines in your shell script IMMEDIATELY AFTER the PREVIOUSLY ADDED error-checking code block to force the user to enter a valid number: while [ $mark -lt 0 ] || [ $mark -gt 100 ] do    read -p "Invalid number range. Enter a mark (0-100): " mark done

# Save your editing session and exit the text editor (eg. with vi: press '''ESC''', then type ''':x''' followed by '''ENTER''').

# Run your shell script by issuing: ./~~for~~if-5.bash # When prompted, enter a '''letter ''' instead of a ''number''. What happens? Does the shell script allow you to enter an '''invalid grade ''' like '''200''' or '''-6'''? Let's reinforce '''math operations''' in a shell script (that you ~~learned~~ created in '''tutorial 10''') and then incorporate math operations within a loop.

# Use a text editor like vi or nano to create the text file called '''for-6.bash''' (eg. vi for-6.bash) If you are using the nano text editor, refer to notes on text editing in a previous week in the course schedule.

# Enter the following lines in your shell script: #!/bin/bash value=1 while [ $value -le 5 ] do   echo "$value"   value=value+1 done

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Tutorial12: Shell Scripting - Part 2

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