Questions

1. What is the file descriptor number for stdin?
   1. 0
   2. 1
   3. 2
   4. 3
2. Which of the following operators is for stdin?
   1. >
   2. >>
   3. <
   4. <<
3. What will happen if you run this command?

   tr [:lower:] [:upper:] < filelist.txt > filelist.txt
   

   1. The filelist.txt file will get overwritten with updated output.
   2. The output of tr will be appended to the end of the file.
   3. You’ll receive a warning message.
   4. The contents of the filelist.txt file will be wiped out, and you’ll be left with just an empty file.
4. What is the default stdin device?
   1. keyboard
   2. terminal
   3. mouse
   4. a named pipe
5. Which of these operators would you use to send stderr and stdout to the same place?
   1. 2>1&
   2. 2>&1
   3. 2...