What am I doing wrong in the this Unix Shell Script? Write a shell script to sen

Question

What am I doing wrong in the this Unix Shell Script?

Write a shell script to send a customized mail message to the users listed on the command line by login (user) name, only if they are currently logged on.

·         If no users are listed on the command line an error message should be printed.

·         In the mail message, you should use the full (real) name from the passwd file (/etc/passwd).

·         You also need to sign the script with the real name of the person who is running the script.

·        

o    This can be derived from the $USER environment variable and looking up the value in the password file.

·         An error message should be printed if the user does not exist in the passwd file or in NIS (YP)

·         The password information on cybserver.uml.edu is stored in NIS (Yellow-Pages YP).

o    You can use  ypmatch<username> or  ypcat passwd to get the information

·         On ce.uml.edu, the information is both in /etc/passwd or can be extracted in the manner listed above.

·         PLEASE ONLY SEND THIS MESSAGE TO USERS WHICH YOU KNOW PERSONALLY.

·        

o    You can always use yourself and me as a test case

o    The real name of the user of the script should only be computed once.

·         A "Here-Document (In-Line Redirection)" must be used for the mail message.

·         No temporary files shall be used.

The message should be as follows:

Hello <INSERT THE USERS REAL NAME FROM THE PASSWORD FILE>,

**** This email is automatically generatated by <username of the person running the script> ******

My instructor requires that I send this message as part of an assignment for class 92.312.
The current time and date is <insert the date/time when the script is executing>.

Have a nice day.

<insert the real name of the person running the script - do not hard code the value>

#!/bin/bash

if who | sed 's/ .*//g' | sort -u | grep "$*" > /dev/null
then
echo "$*" is logged in
else
echo "$*" not logged in
fi
if [ "$*" -eq 0 ]
then
echo no user specified
fi

mail "$*" << message
Hello `awk -F: '{print $5}' /etc/passwd` please ignore this mail. My instructor requires that I send this message as part of an assignment. The current time and date is `date`. Have a nice day `$USER`.

END

error message:

-bash: [: -eq: unary operator expected
-bash: warning: here-document at line 14 delimited by end-of-file (wanted `message')

Explanation / Answer

#! /bin/sh -xv USER="getent passwd `whoami` | cut -d ':' -f5 | cut -d ',' -f1" #if there are no POSIT PARAMS, i.e. #usernames, listed, print an error #MSG and bounce out if [ "$1" -eq 0 ] then echo "no user specified" fi #I want to protect against false positives, #e.g. don't match maryjane or maryann to #mary for user do case $1 in #this matches ONLY the correct username "") if who | cut -c1-8 | sed 's/ .*//g' | sort -u | grep -w $1 > /dev/null then echo "$1 is logged in" mail "$1"

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