$($c$)(2$ points$)$ Give the command to produce the file listing as provided above.

$12.$ Consider the following bash script and answer the questions that follow the line numbers are used so questions can refer to specific lines$)$:

$1.$ #$!/$bin$/$bash

$2.$ # Assign $$1$ argument to $dir, if $$1$ is empty, use'$\text{'}$ as default.

$3.$ dir$=$$$\{1-\text{'}.\text{'}\}$

$4.$ if $[-$d $"$$dir" $]$; then

$5.$ echo "Files found: $$($find $"$$dir" $-$type $ $|$ wc $-1)."$

$6.$ echo "Dirs found: $$($find $"$$dir" $-$type d $|$ wc $-1)."$

$7.$ else

$8.$ echo $"[$ERROR$]$ Please retry with another folder."

$9.$ exit $1$

$10.$ f$1$

$($a$)(2$ points$)$ Name and explain the purpose of #$!/$bin$/$bash in line $1.$

$($b$)(2$ points$)$ Explain what line $3$ does.

$($c$)(2$ points$)$ Briefly explain what the if$-$statements checks in line $4.$

$($d$)(5$ points$)$ Explain the line $5$ and $6,$ paying special attention to the piping command $($vertical bar$).$

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