Need some assistance for Linux shell scripting

[D13H4RD]

Hello. I'm currently in the midst of doing a Linux terminal shell-script for an assignment. The assignment requires that we create a shell script which backs up all files with a certain extension throughout the Linux system. Basically, if we enter ".txt", all files with that extension will be backed up. The requirements are as follows;

 

• The script should first ask a user if they'd like to load a saved preset. If yes, it prompts which preset to load, in which it executes from there.
• If the user decides to not load a preset, the script then asks for the desired filetype extension that is to be backed up, along with the desired destination path.
• The inputs for above should also be saved into a preset file so that it can be quickly accessed in the future. This should be named by the user.
• The backup process should also be logged into a log.txt file.

This is what I've got so far;

#!/bin/bash

function introduction(){
	echo "Welcome to this totally simplified backup utility!"
    echo "Please specify if you would like to use a pre-determined setting."
    read setpreference
    if [ "$setpreference" == "Yes"] || [ "$setpreference" == "yes" ]; then
    	echo "Entered the desired preference file"
        read preffile
	elif [ "$setpreference" == "No" ] || [ "$setpreference" == "no" ]; then
    	main
	fi
}

function main(){
	echo "Enter the desired filetype you would like to backup"
    read filetype
    echo "$filetype" > config.txt
    backuptime='date +%b-%d-%y'
    echo "Enter the path and directory of the desired destination"
    read destination
    echo "$destination" >> config.txt
    
    tar -cpzf $destination
    
    echo "Backup successful"
}

Sorry to all the seasoned Linux users for the hodgepodge. But I'm totally new to this sort of thing and I really do need help.

 

There's also a second part of the assignment which involves creating another script to evaluate the functionality of the first but I'll explain that later.

[Sauron]

What exactly do you need help with?

[D13H4RD]

2 minutes ago, Sauron said:

What exactly do you need help with?

Mainly getting the script to recognize user inputs to place into a configuration file that is named by the user, which can then be loaded the next time the script is used so that parameters such as file type and save location need not be re-entered manually 

 

The actual backup portion should be straightforward. It's that part that trips me up. 

[Dat Guy]

Hint: You should not assume that there is a bash at /bin/bash.

[D13H4RD]

1 hour ago, Dat Guy said:

Hint: You should not assume that there is a bash at /bin/bash.

Just learned about that. Thanks!

[wasab]

You can get user arguments using the $1 variable. 

 

Then use something like cp *.txt /backupDir to just copy all the files there. 

[Sauron]

21 minutes ago, D13H4RD said:

Just learned about that. Thanks!

/bin/sh should be on every system though

4 hours ago, D13H4RD said:

Mainly getting the script to recognize user inputs to place into a configuration file that is named by the user, which can then be loaded the next time the script is used so that parameters such as file type and save location need not be re-entered manually 

 

The actual backup portion should be straightforward. It's that part that trips me up. 

You could use grep

 

Appending a value to a file is as easy as

echo "Key Value" >> file

 

[Dat Guy]

1 minute ago, Sauron said:

/bin/sh should be on every system though

True, but you should make sure to avoid bashisms.

[D13H4RD]

12 minutes ago, Sauron said:

 

echo "Key Value" >> file

 

Much like 

 

“$destination” >> config.txt?

[Sauron]

41 minutes ago, D13H4RD said:

Much like 

 

“$destination” >> config.txt?

I'm pretty sure you need echo. Also you should add a key, otherwise you won't be able to retrieve the value later

echo "Destination $destination" >> config.txt

 

[D13H4RD]

1 hour ago, Sauron said:

I'm pretty sure you need echo. Also you should add a key, otherwise you won't be able to retrieve the value later

echo "Destination $destination" >> config.txt

 

Didn't know about the key. Thanks.