Question

So, I have a text file that is organized like this

<username>:<fullname>:<usergroups>

I need to create a new user for each line and put them into their groups. I am stuck with trying to set username into a variable to use with useradd. I have tried using cut but it needs a file name, I can’t just pass it a line.

Here is what I currently have:

#! /bin/bash
linesNum=1 
while read line
do
  echo
  name=$( cut -d ":" -f1 $( line ) )
  ((lineNum+=1))
done < "users.txt"

Thanks for your help!

Answer 1

#!/bin/bash
while IFS=: read username fullname usergroups
do
    useradd -G $usergroups -c "$fullname" $username
done < users.txt

fullname is the only string that should contains whitespace (hence the quotes), A list of usergroups should be separated from the next by a comma, with no intervening whitespace (so no quotes on that argument) and your username should not contain whitespace either.

Upate:

To get the list of usergroups to create first you can do this…

#!/bin/bash
while IFS=: read username fullname usergroups
do
    echo $usergroups >> allgrouplist.txt
done < users.txt

while IFS=, read group
do
   echo $group >> groups.txt
done < allgrouplist.txt

sort -u groups.txt | while read group
do
   groupadd $group
done

This is a bit long winded, and could be compacted to avoid the use of the additional files allgrouplist.txt and groups.txt but I wanted to make this easy to read. For reference here’s a more compact version.

sort -u < $(
       echo $(while IFS=: read a b groups; do echo $groups; done < users.txt )
      | while IFS=, read group; do echo $group; done ) 
| while read group
do
       groupadd $group
done

_{(I screwed the compact version up a bit at first, it should be fine now, but please note I haven’t tested this!)}