This command shows the File Descriptor $($FD$)$ in this output. The character after the number i$.$e $1$u$,$ represents the mode in which the file is opened. r for read, w for write, u for read and write.

$.$

What does the file descriptor $"3$u$"$ represent?

$.$

$.$

$($Hint: It's not a standard stream$)$

$($Difficultly: Basic to Intermediate$)$

$.$

q$4$a$.$png

$.$

$.$

The following output is intended to be an additional aid towards answering the above question:

q$4$b$.$png