I'd like to find a user who was added from `/etc/passw` with `useradd` command.

Ubuntu 22.04

There are several people (about 10 people) logged in and using Linux machines.
When adding a new user, use the useradd command.

Look at the following site and see
https://uxmilk.jp/8530

You can check the list of users with the following command:

$cat/etc/passwd
  root:x:0:0:root:/root:/bin/bash
  bin:x:1:1:bin:/bin:/sbin/nologin
  ...
  nginx:x:498:499:nginx user:/var/cache/nginx:/sbin/nologin

However, users related to services such as nginx and docker are also displayed.

useradd How do I find the users that I have added with the command (that corresponds to the real person)?

/home I think I can solve this problem by looking for a user linked to the directory, but I didn't know if this was really correct, so I asked.

$cat/etc/passwd|grep/home
syslog:x:102:106::/home/syslog:/usr/sbin/nologin
alice: x:1000:1000:alice,,,,:/home/alice:/bin/bash

linux

2023-02-24 01:39

1 Answers

useradd(1)

-u, --uid UID

The numerical value of the user's ID. This value must be unique, unrequited the -o option is used. The value must be non-negotiable. The default is to use the small ID value greater than equal to UID_MIN-r, --system

System users will be created with no aging information in /etc/shadow, and their numerical identifiers are selected in the SYS_UID_MIN-SYS_UID_MAX range, defined in /etc/login.defs, install of the UID

Therefore, you can check it as follows, but it is not perfect because you can create a regular user by specifying uid other than UID_MIN to UID_MAX.

$readuid_minuid_max<<$(awk'/^UID_/{print$2}'/etc/login.defs|xargs)
$ awk-F:-vmin=${uid_min}-vmax=${uid_max}'$3>=min&&$3<=max'/etc/passwd

2023-02-24 05:12

If you have any answers or tips

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