Exercise-1

Write a shell script named daily-backup.sh that does the following:
Discovers all users defined on the system excluding system and services users.
For each of these users, locates the home directory and create an compressed archive for this directory (.tar.gz).

Creates a global archive that contains all archived users home directories and save it in /var/backup.
The script should be daily run at 1AM and for each execution, the global archive name should reflect the date of the archive creation.
The shell script should produce a log file under /var/log/daily-backup.log to which will be added each day the following information: date of script execution, result of each user home directory archiving (archive name, size, and archive process result code) and same information about the global archive file

The script should send a summary report in email to root@localhost at the end of each execution containing date, total time of execution, encountered problems.

Exercise-2

Write a shell script that swaps the contents of two files. The shell script should be called swap.sh.
The swap.sh script should take two arguments as input. They indicate the two files to be swapped. You should check that the proper number of arguments have been passed and that the filenames passed on the command line have the proper permissions set. You should also check that any temporary files used during the execution of the script do not exist. If any of these checks fail, then print an appropriate error message and exit the script with a status of one. If all of the checks pass, then swap the two specified files and print a message indicating that the two files have been swapped. 
Example :
$ swap tmp1 tmp2 
The files mp1 and tmp2 have been successfully swapped. 
Exercise-3

Write a shell script (named outfile.sh) that reads all file names passed on the command line and -depending on the option that is used- write the files names out in all uppercase letter (if the option is -u), write the files names out in all lowercase letter (if the option is -l) or prints the contents of files on the screen (if the option is -p). 
Remark: Implement this shell using your own function upper(), lower() and print().

General Remarks: In all of your shell script assignments, be sure to 
1. Put the comment at the beginning of the script to indicate to the system that the Bash is to be used; 
2. Put comments after that line to identify yourself, the assignment and to describe the general purpose of the script; 
3. Put an appropriate comment before each block of commands in the script; 
4. Exit with a status of zero when the script was able to correctly accomplish its task; and print an appropriate error message and exit with a nonzero status when the script was not able to accomplish its task.