4.9 Three tcsh scripts

• Write a prime number program using the "C" shell. Accept an argument and print out all prime numbers less than the passed argument. (Look at factor(1).)
• Get current earthquake information from the Internet. Look at the quake alias for starters. (The Internet keeps changing.) Strip out all of the data except the large earthquakes (grep). Place this information in a file (create it if necessary). Then take this file and sort (sort) it. After it is sorted remove lines that are the same (uniq). Display this result and place it back into the above file for next time. This should work in such a manner that if you run it at a later date, the file accumulates earthquake information. The shell script needs to store information from one login to the next.
• Process the /etc/passwd file to create a list of unique user numbers and a list of unique group numbers. Title each list.
• List the last (about) 25 users that are on (were on) the system in alphabetic order by user name. Use the

  last -100
  

  command to create a list of possible users. Then use cut, sort, and uniq to arrange the list.
• Write a "tree" script. Do a recursive directory search and display it with an indented format. There is no need to attempt to use special graphic characters. As the first and only required argument, pass the path location to start your tree. Do not display the files in the directories, unless that is an option of your shell script.
• Write a "useful" shell script, and a note to me explaining why it is useful.

your name
TABER CSC137
Lab 4.9: Three tcsh scripts