For your second assignment, you will write a shell script that builds on those skills that you developed

so far this semester and with the first assignment. However, instead of an analysis tool, you will build a

system administration tool that provides functionality for file backup and restoration. You will need to

determine characteristics of files, perform operations on files $($in this case, compression$),$ and be able to

add and extract files from an archive file $($in tar format$).$

Rather than providing an interactive menu, this time you will provide for all functionality of the script

by evaluating the command line $($its options, a$.$k$.$a$.$ flags, possibly with arguments; and positional

parameters$)$ and environment variables. This might make the script more appropriate for use via cron or

remote execution.

The name of the archive file to use $($create$,$ modify, or query$)$ will be passed to the script on the

command line. Additionally, the following flags and actions will be supported:

$-$b : backup a copy of filename from the filesystem into the archive, but only if $(1)$ it

is not already in the archive or $(2)$ if it is newer than the version in the archive. If filename does

not exist in the filesystem to be archived, silently exit with error code $7.$

$-$r $$ filename $>$ : restore filename to the filesystem from the archive; however if a version of the

file already exists in the filesystem and that existing file is older than the version from the

archive, then extract the file from the archive to the current directory as filenamenewer. If

filename does not exist in the archive, silently exit with status code $14.$

$-$c : gzip compress the file being backed up $($not the archive, just the file as indicated by the $-$b

flag$)$ before adding to the archive; calculate the percentage saved by compressing that file and

append a line consisting of the following comma separated fields:

the current system date and time, filename, and the saved amount $($as a percentage$)$

to the logfile$.$ The logfile will have be named, either, the value of the A $2$ LOG environment

variable $($if it is set$)$ or assign$2.$log $($if the environment variable A$2$LOG is not set$).$

If an invalid flag $($an option not b$,$ r $,$ nor c $)$ is passed to the program, print "Invalid Option" to stderr and

exit with a return status code of $3.$

Graduate students will also need to provide the additional following functionality.

If the $-$c option is provided, but the $-$b option is not, then exit silently with return status code of

Only when processing the $-$b flag, if the file to add to the archive is not readable or if the archive

is not writeable print the message "Archive access failure" to stderr and exit with return status

code $6.$

Only when processing the $-$r flag, if the archive file to restore from does not exist or is not

readable, print the message "Archive retrieval failure" to stderr, and exit with return status code

Your script submission must be a text file uploaded to Brightspace $($for full credit it must be posted on$.$ script should be bash file for opensuse $15\mathrm{.}6$ linux patform vi script.