Sorry about the first post, here's one using the template, the code has changed a little bit. I got the Shell error loop working, but not the way it's supposed to be. It's supposed to repost the list and everything. Same with the username error message.
1. The problem statement, all variables and given/known data:
Write a shell script to add individual users to a Linux system. The script should prompt for the username to create and ensure the username is unique on the system. (Be sure your check for uniqueness actually works-bo, bob, and bobby should all be creatable, if they do not already exist on a system.)
The script should also obtain the user's full name and obtain the preferred user shell. (Be sure to display a valid list of shells prior to shell selection.)
2. Relevant commands, code, scripts, algorithms:
I mainly need help with an error loop, not sure what should be put in here.
3. The attempts at a solution (include all code and scripts):
4. Complete Name of School (University), City (State), Country, Name of Professor, and Course Number (Link to Course):
Bismarck State College, Bismarck ND, US, Nick See, CIS 223-01
Here's a small script that might give you an idea about doing your user name error loop. It's not the only way, but should serve as a clue. It continues to prompt until you enter the command "quit."
Code:
#!/usr/bin/env bash
c=""
while [[ -z $c ]]
do
printf "enter cmd "
read c
if [[ $c != "quit" ]]
then
c=""
fi
done
exit
You also need to think about the full name. I'm assuming it will have a space which unless properly handled on the command line to useradd might cause problems.
Actually, you don't need the if. If grep returns a non-zero (no match) then the while will stop executing and the username in the variable will not exist in /etc/passwd.
Your problem here is that if the user "scooter" exists but "sco" does not, it will not let you create "sco" because the command cut -d: -f1 | grep "sco"would return non-zero (sco would be a match for scooter). Have a look at the manual page for grep and see if there are any options that you might add to ensure that "sco" and "scooter" would not be a match.
Alright so I pretty much have the script working, it's not exactly how the teacher wants. It doesn't loop the whole bash shell list and the Enter username parts. But like you said, I am running into the grep error, any hints for a quick fix to that would be awesome, right now I'm searching all the pages on grep I can looking for the correct filter to put in.
Could I just put it like | grep -x $userName ? because according to linuxabout.com -x will only take the whole thing.
Anyways, in case anyone cares here's the code I came up with so far.
Code:
#!/bin/bash
echo ""
echo "Please enter your username: "
read userName
cut -d: -f1 /etc/passwd | grep $userName > /dev/null
OUT=$?
while [ $OUT -eq 0 ]
do
echo "That username already exists, please try a different name: "
read userName
cut -d: -f1 /etc/passwd | grep $userName > /dev/null
OUT=$?
done
echo "Please enter your full name."
read fullName
echo "Available Shells"
echo "----------------"
echo "/bin/sh"
echo "/bin/bash"
echo "/sbin/nologin"
echo "/bin/tcsh"
echo "/bin/csh"
echo "/bin/ksh"
echo "Enter the user's shell: "
read regShell
until [ $regShell = "/bin/sh" ] || [ $regShell = "/bin/bash" ] || [ $regShell = "/sbin/nologin" ] || [ $regShell = "/bin/tcsh" ] || [ $regShell = "/bin/csh" ] || [ $regShell = "/bin/ksh" ]
do
echo "Invalid shell, try again: "
read regShell
done
useradd -c "$fullName" -s $regShell $userName
if [ $? = 0 ]; then
echo "User was created successfully."
fi
edit: grep -x did nothing, even tried grep -x "^$userName$", that didn't work. My textbook only has 5 pages about grep, none of which describe they just say use it, and the only extension they use is -i which makes the command disregard caps. hrmm.
Interesting. I did have another option in mind (-w), but -x should have worked too since cut output is just the one word which would/should satisfy -x too. When I tried -x with a snipit I copied from you post it worked just fine.
---------- Post updated at 22:03 ---------- Previous update was at 21:56 ----------
Looked more closely at your -x example. You might have needed "^$userName\$"
right now I'm just stuck on the grep issue.. I've tried everything -w, -x, -x ^'$userName\$', -w ^$userName\$, ^$userName$@, ^$userName\$@, ^$userName$*
Any clues as to what I could use? If user Bob exists Bo cannot be created. Smashing my head on my desk right now. The script works.. but like I said, I can't create Bo if Bob already exists.
Code:
#!/bin/bash
echo ""
echo "Please enter your username: "
read userName
cut -d: -f1 /etc/passwd | grep $userName > /dev/null
OUT=$?
while [ $OUT -eq 0 ]
do
echo "That username already exists, please try a different name: "
read userName
cut -d: -f1 /etc/passwd | grep -w '^$userName$' > /dev/null
OUT=$?
done
echo "Please enter your full name."
read fullName
echo "Available Shells"
echo "----------------"
echo "/bin/sh"
echo "/bin/bash"
echo "/sbin/nologin"
echo "/bin/tcsh"
echo "/bin/csh"
echo "/bin/ksh"
echo "Enter the user's shell: "
read regShell
until [ $regShell = "/bin/sh" ] || [ $regShell = "/bin/bash" ] || [ $regShell = "/sbin/nologin" ] || [ $regShell = "/bin/tcsh" ] || [ $regShell = "/bin/csh" ] || [ $regShell = "/bin/ksh" ]
do
echo "Invalid shell, try again: "
read regShell
done
useradd -c "$fullName" -s $regShell $userName
if [ $? = 0 ]; then
echo "User was created successfully."
fi
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