Unix/Lunix Programming

Exercise 4

Read the following script process_cmd_arg and answer the question.

usage () {

echo "usage: program [-f file | -i]"

}

# process command line argument

interactive=

filename=

while [[ -n $1 ]]; do

if [[ "$1" == "-f" ]]; then

shift

filename=$1

elif [[ "$1" == "-i" ]]; then

interactive=1

elif [[ "$1" == "-h" ]]; then

usage

exit

else

usage >&2

exit 1

fi

shift

done

Trace the values of the following variables during the execution of a given command.

Command: process_cmd_arg -f outputFile

interactive
filename
$1

Command: process_cmd_arg -i

interactive
filename
$1

Command: process_cmd_arg -h

interactive
filename
$1

Command: process_cmd_arg -f outputFile -i

interactive
filename
$1