Help a NOOB with IF/while conditioning

[Kwiz]

Scripts Purpose: Display all processes running for specific users, if NO username is entered then all processes will be displayed

So far i have

#!/bin/bash

x=1

check="cat /etc/passwd | cut -f1 –d “:” | grep $user”
echo –n “enter a username or press enter for all processes ‘user’:”
read user

until [ “$x” = 1 ]
do
	if [ “$user” = “$check” ]
	then
		ps aux | grep $user | less
		x=1
	else
		if [ “$user” = “” ]
		then
			ps aux | less
			x=1
		else
			echo “The username is incorrect”
		fi
	fi
done

I THINK there is a problem with $check comparing it to $user?

I need it to compare the name types in to current users incase of a mismatch.

[atreyu]

You're close, but I'd change it up a little:

#!/bin/bash

users=$(cat /etc/passwd|cut -f1 -d:)
printf "$users\n"
until [ -n "$user_ok" ]; do
  echo -en "\nEnter a username or press enter for all processes: "
  read user
  if [ -n "$user" ]; then
    for check in $users; do
      if [ "$check" == "$user" ]; then
        user_ok=1
        break
      fi
    done
    if [ -z "$user_ok" ]; then
      echo "The username is incorrect"
      unset user
    fi
  else
    user_ok=1
  fi
done

if [ -n "$user" ]; then
  ps -f -u $user|less
else
  ps -ef|less
fi

If a username is entered that is wrong (i.e., does not appear in /etc/passwd), then the script will continue to prompt for a valid username until one is received. This can be easily changed to abort the script, if you want.

If no name is entered (i.e., they hit [Enter]) then that is considered a valid response, too.

The format of the ps command at the end can be changed, too. That is just one example of how to customize the ps output.

[Kwiz]

Hey thanks for the reply.

I should of taken a break for a while but i ended up getting it to work with

#!/bin/bash

until [ "$x" = 1 ]
do
clear
read -p "Enter Username: " user
If [ "$user" ]
then
       check=$(egrep -w $user /etc/passwd | cut -f1 -d":")
       if [ "$user" = "$check" ]
           then
                ps aux | $user | less
                x=1
           else
                read -p "username does not exist press ENTER]to continue"
        fi
else
       ps aux | less
       x=1
fi
done

I was just over thinking it but you are right i should be listing the content/users 1st so they know what to choose from. If you've got any tips in writing/modifying/layout of scripts im all ears.

Thanks!

[atreyu]

Ah, I misunderstood what your check command was doing before. I thought you initially wanted to display all potential users. Yeah, now I see...

Btw, the reason I did the ps -f -u $user was b/c that way only shows processes owned by said $user. Running ps auxw|grep $user shows all processes that happen to match an occurrence of $user in the output. It probably would show the exact same processes, but the difference is worth mentioning.

On this line of your code (i assume you know the If is a typo):

 If [ "$user" ]

you should really make that:

if [ -n "$user" ]

And when using the equals sign to compare, you should use double-equals, e.g.:

[ "$x" == '1' ]

Single equals should only be used for assigning values.

As for other tips, I'd recommend checking out the scripts in /etc/init.d/. They are a good repository of layout ideas and examples of esoteric bash functions and what not in action.

[Kwiz]

Thanks so much for the help this script does exactly what i need it to do now.
Thanks for the tips to iii keep them in mind