Use execve to write a program called myls whose behavior is identical to the$()/($b$)$

i$($n$)/($l$)$s program. Your program should accept the same command$-$line argu$-$

ments, interpret the identical environment variables, and produce the identical

output.

The ls program gets the width of the screen from the COLUMNS environ$-$

ment variable. If COLUMNS is unset, then $1$ s assumes that the screen is $80$

columns wide. Thus, you can check your handling of the environment variables

by setting the COLUMNS environment to something less than $80$ :

linux$>$ setenv COLUMNS $40$

linux$>(.)/($m$)$yls

:$(()/())/($ O$)$utput is $40$ columns wide

linux$>$ unsetenv COLUMNS

linux$>(.)/($m$)$yls

:$(()/())/($ O$)$utput is now $80$ columns wide