Shell Programming and Scripting

paul.obrien16@aisling:~/os$ bash checklogin
: command not found
Enter username
paul.obrien16
': not a valid identifier `username
checklogin: line 36: syntax error: unexpected end of file
paul.obrien16@aisling:~/os$

#!/bin/bash

# get username
echo "Enter username"
read username
#finds the user in the list of people currently logged in
if [ $ cat /etc/passwd | cut -d: -f1= "$username" ]
then
# loop while user is logged in
while [ $(who | grep $username) != 0 ]
do
sleep 60
done

echo "$username logged in"
#generate beep
echo -e \a
#output to a log file calles date.txt
echo "user is $(username) Today's date is $(date)" > /tmp/date.txt
#exit function
exit 1
else
#display message
echo "$username aint logged in!"
#output to a log file called date.txt
echo "user is $(username) Today's date is $(date)" > /tmp/date.txt
#exit the function
exit 1
#end the script
fi

exit 0

if [ $ cat /etc/passwd | cut -d: -f1= "$username" ]

if grep -q "^${username}:" /etc/passwd
then
...

while [ $(who | grep $username) != 0 ]

# there really are 'true' and 'false' programs, so go ahead and
# try these statements
if true
then
       echo "true returns true"
fi

if ! false
then
        echo "false returns false"
fi

while who | grep -q "${username}"
do
...

exit 1