How to add a unix/linux user in a bash script

Here’s my test bash script. I’m not able to get it to work. I’m seeing two errors:

1. Use of uninitialized value $answer in chop at /usr/sbin/adduser line 589.
2. Use of uninitialized value $answer in pattern match (m//) at /usr/sbin/adduser line 590.

Here’s my script:

#!/bin/bash
sudo adduser myuser << ENDX
password
password
First Last




Y
ENDX
exit 0

Here is the output:

<a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="026f67426f7b616d6f7277766770">[email protected]</a>$ ./adduser.sh 
Adding user `myuser' ...
Adding new group `myuser' (1001) ...
Adding new user `myuser' (1001) with group `myuser' ...
Creating home directory `/home/myuser' ...
Copying files from `/etc/skel' ...
Enter new UNIX password: Retype new UNIX password: passwd: password updated successfully
Changing the user information for myuser
Enter the new value, or press ENTER for the default
        Full Name []:   Room Number []:         Work Phone []:  Home Phone []:  Other []: Use of uninitialized value $answer in chop at /usr/sbin/adduser line 589.
Use of uninitialized value $answer in pattern match (m//) at /usr/sbin/adduser line 590.
Is the information correct? [Y/n] <a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="325f57725f4b515d5f4247465740">[email protected]</a>$

This is on Kubuntu 12.04 LTS

$ bash --version
bash --version
GNU bash, version 4.2.25(1)-release (x86_64-pc-linux-gnu)

Here are the lines from adduser (system script – unmodified by me) with notations of the two relevant line numbers:

for (;;) {
       my $chfn = &which('chfn');
    &systemcall($chfn, $new_name);
    # Translators: [y/N] has to be replaced by values defined in your
    # locale.  You can see by running "locale yesexpr" which regular
    # expression will be checked to find positive answer.
    print (gtx("Is the information correct? [Y/n] "));
    chop (my $answer=<STDIN>);        <-- LINE 589
    last if ($answer !~ m/$noexpr/o); <-- LINE 590
}

Answers:

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Method 1

Just use the command line parameters instead of stdin, and use chpasswd for the password.

For example:

sudo adduser myuser --gecos "First Last,RoomNumber,WorkPhone,HomePhone" --disabled-password
echo "myuser:password" | sudo chpasswd

Method 2

adduser calls the external program chfn to read the full name and other user information. chfn reads a bufferful of input, including not only what it needs but that last Y line. When adduser asks for confirmation afterward, the Y line has been read (but ignored) by chfn, so adduser sees an end of file on its input. The variable $answer is expected to contain a line of input, but because there was no input to read, it is undefined.

Since you’re writing a script, pass the data (except the password) on the command line.

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0