Creating a Simple Unix Shell Script

A script is a plain text file containing commands.

Your scripts should be in a directory in your $PATH

Your scripts need to be "executable"

#!/bin/sh
# This is a comment. Comments are good.
# This is my first shell script.
echo "System Status Report"
date

echo -n "System uptime and load:"
;  uptime

echo -n "Operating System: " ; sysctl -n kern.ostype
echo -n "OS Version: " ; sysctl -n kern.osrelease
echo -n "OS Revision number: " ; sysctl -n kern.osrevision
echo -n "Hostname: " ; sysctl -n kern.hostname

bytes=`sysctl -n hw.physmem`
megabytes=`expr $bytes / 1024 / 1024`

echo "Physical memory installed
(megabytes): $megabytes"

Tasks:

In the example script is -n an argument or an option?
What do you think $bytes and $megabytes mean in the last two lines?
Which commands are used in the sample script?
Which lines of the script use more than one command?

Previous - Opening Files from the Command Line		Next - Take a short break
	Home