Using Shell Scripting Array Variables - Exercise

Reviewing how variables are used

Exercise scoring

Instructions

# Two-step database file conversion script 
if [ $# <> 2 ];  then
echo Error: Please include 1) a file to convert 
echo and 2) a username on the command line. 
echo (e.g. switch hotelreg.dat thomasa)
echo Contact the sys admin for assistance
exit
fi
if [ -f $1 ]; then
if [ ‘grep -c $2 /etc/passwd‘ ]; then
convertdb $1 -user $2 > tmp.$$
filterdb tmp.$$ > $1
fi
fi

1. What is the first if statement testing to ascertain?
2. The second if statement tests for the existence of a file. What file's existence is being ascertained?
3. The third if statement uses the grep command to search for a string. What string is being searched for?
4. Why is $$ used to create a unique filename?
5. On the line with filterdb, what does the $1 represent? Is it the same as the $1 in the second if statement?

Submitting your exercise