Arrays in useradd command

Kai' · 04-29-2008, 05:05 AM

ok, so I tried using arrays to create X amount of users. I made an arrayname called 'users' using declare -a. I set the variable user to:

(smith ocelot derek)

and then I use the useradd command but I wanted to use a value that represented all the values rather than listing arrays like this:

$ useradd ${name[0]}
$ useradd ${name[1]}
$ useradd ${name[2]}

or, I also tried using a file called 'user' using the same structure
as the usenames above but is this form:

(smith
ocelot
derek)

and using the cat command...

$ cat user|useradd

but that didn't work, so what would be the best way to add all the users at
one command (help on either method would be appreciated)

colucix · 04-29-2008, 05:45 AM

You cannot create more than one user at a time with useradd command, so you have to cycle over the content of the array and execute the useradd command on each element. You can use a for loop:

Code:

for i in $(seq 0 10)
do
  echo useradd ${users[$i]}
done

If you have a list of user names stored in a file, you can read the file one line at a time using a for loop like this

Code:

for name in $(cat testfile)
do
  echo useradd $name
done

pixellany · 04-29-2008, 06:22 AM

If you have an array named "usr":

Code:

for i in `seq 0 $((${#usr[*]}-1))`; do useradd {usr[$i]};done

${#usr[*]} gives you the size of the array, as does ${#usr[@]}

I could have added 50 users by hand in the time it took to figure this out......

<<edit>> or colucix could have posted the same basic answer but much faster......!!