The file emails.log contains 12 lines. Predict the exact output of each of the following, and explain the difference using how each command learns about the file: wc -l emails.log wc -l < emails.log

Describe, in order, how the shell sets up the streams for a command before the program runs. Your description must be a single set of rules that correctly predicts all five rows. In particular, it must account for: why experiments 3 and 4 give different results even though both contain a > redirection and a 2>&1; and why, in experiment 5, ALERT appears on the terminal yet is not included in the count printed by wc -l.

What does ls -a add to that listing?

List the final contents of lab and of archive after the whole line finishes. Then, explain why pwd prints /home/mina/course/lab and why that output would have appeared even if the earlier commands had failed.

You compile a third hello in your current directory. Why must you type ./hello to run it?

(a) Relative to C0, state exactly what the 09:12 commit changes and name two things visible in the 09:10 status that it does not include. (b) Using your answer, justify every line of the 09:15 status. 

Write out the command line after the shell expands the glob (i.e. the exact argument list mv would receive). For each name in lab that is excluded, state the rule that excludes it.

Evaluate each of the two claims in Mina’s explanation. For each claim, identify the earliest point at which her reasoning goes wrong and explain your reasoning. 

Does mv run? Justify using the meaning of && and the exit status of cp.

Answer all three parts. (a) After chmod 640 notes.txt, enter the 10-character permission string exactly as it would appear in the first column of ls -l. (b) Can users in the “other” category read notes.txt? (yes/no) (c) Enter the octal form of rwxr-xr-x.