UNIX Shells by Example (4th Edition)

LAB 59: THE case STATEMENT

1. The ps command is different on BSD (Berkeley UNIX), System 5 (AT&T UNIX), and Linux. On System 5, the command to list all processes is

   ps ef

   On BSD UNIX, the command is

   ps aux

   On Linux, the command is

   ps -aux

   Write a program called systype that will check for a number of different system types. The cases to test for will be

   AIX

   Darwin (Mac OS X)

   Free BSD

   HP-UX

   IRIX

   Linux

   OS

   OSF1

   SCO

   SunOS (Solaris/SunOS)

   ULTRIX

   Solaris, HP-UX, SCO, and IRIX are AT&T-type systems. The rest are BSD-ish.

   The version of UNIX you are using will be printed to stdout . The system name can be found with the uname “s command or from the /etc/motd file.

2. Write a script called timegreet that will do the following:

   1. Provide a comment section at the top of the script, with your name, the date, and the purpose of the program.

   2. Convert the following program to use the case command rather than if/elif .

   #!/bin/bash # Comment section you=$LOGNAME hour=$(date +%H) echo "The time is: $(date +%T)" if ((hour > 0 && hour < 12)) then echo "Good morning, $you!" elif ((hour == 12)) then echo "Lunch time!" elif ((hour > 12 && hour < 16)) then echo "Good afternoon, $you!" else echo "Good night, $you. Sweet dreams." fi