Question

hi I am trying to write a bourne-shell script that takes a name as a parameter and check if the user is logged in and output a message if not.

this is what I got so far but my condition is wrong.

if test "who|grep $1" == "$1" //the problem is that it takes the hole 1st column
then 
  who|grep $1|awk '{print $5}'
else
  echo user not logged in
fi

any help? thanks in advance.

Answer 1

1) Your condition is completely fouled up.

2) Your regex is inaccurate.

3) You’re mixing grep and awk.

4) You’re not quoting your echo argument.

if who | grep -q "^$1\s"
then 
  who | awk -v user="$1" '$1 == user { print $5 }'
else
  echo "user not logged in"
fi

Replacing the first grep with awk is left as an exercise for the reader.