4

I want to find out what 'normal' users are available on a system. By normal, I mean those who are manually created, not those like sshd or gdm.

2

Typically "normal users" are assigned user ID's >= 1000. If this is the case on your system, then the following could work:

awk -F: '{if ($3 > 999) print $1}' /etc/passwd
  • I would add as well to analyze the /etc/group – tmow Feb 3 '11 at 8:22
3

Do grep UID_MIN /etc/login.defs. Then do getent passwd and look which users have a UID >= the UID_MIN value from above.

Explanation: Whenever a user is manually added, it grabs the first available UID >= the UID_MIN value from login.defs (unless UID is manually specified)

  • indeed your solution is nice, but /etc/login.defs is used on GNU/Linux systems and doesn't apply on all the unix flavors. Then getent is not a standard as well, but just a tool. – tmow Feb 3 '11 at 8:20
  • @tmow, Ya, its OS dependent. And getent is on all the linux and solaris boxes we run, so seems to be common enough. – Patrick Feb 3 '11 at 23:22
2

I don't think there's a way to tell which users have been "manually created". Probably the best you can do is look for users that have a valid shell, as typically system users like sshd and gdm have shells like /bin/false and /sbin/nologin to prevent logins. The list of valid shells is in /etc/shells, so you can use grep to get a list of users with one of those shells:

$ grep -f /etc/shells /etc/passwd

If you just want usernames:

$ grep -f /etc/shells /etc/passwd | cut -d: -f1
1
ls -l /home

But that's also not the most reliable source.

If once logged in:

lastlog | grep -v 'Never logged in'
  • 1
    Another reason it's not reliable is that you may remove a user without removing their home directory. – tshepang Jan 31 '11 at 17:50

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