Looking for specific user ID's from the passwd file

LinuxRacr · #1 (**permalink**) 08-24-2007

Hello,

My issue is that I want to look for specific users that have their first and last initial followed by four numbers. For example:

ab1234

I've already got the user ID's out of the passwd file

Code:

more passwd | awk -F ":" '{print $1}' > userids

I just need to know how to just pick the users out of the list that are formated:

aannnn

a=alphabet
n=number

Thanks in advance!

waiq · #2 (**permalink**) 08-24-2007

from the top of my head. I think you can use somthing like this:
grep -e ^[:alpha:][:digit:]*

LinuxRacr · #3 (**permalink**) 08-24-2007

Thanks for the replay. Will that account for all the different userids that fit that pattern I mentioned above?

EDIT: I tried the following:

Code:

more passwd | awk -F ":" '{print $1}' | grep -e ^[:alpha:][:digit:]

and got a few users I didn't want like:

lp
adm

and some other users who didn't fit the EXACT pattern I asked for above.

I want to be able to list all users that fit the pattern below;

aannnn

example:

ab1234

Unbeliever · #4 (**permalink**) 08-24-2007

Code:

more passwd | awk -F ":" '{print $1}' | grep '[A-Za-z][A-Za-z][0-9][0-9][0-9][0-9]'

LinuxRacr · #5 (**permalink**) 08-24-2007

Unbeliever. That was the perfect answer! Thanks. I learn more everyday.

Unbeliever · #6 (**permalink**) 08-24-2007

Code:

more passwd | awk -F ":" '{print $1}' | egrep '[A-Za-z]{2}[0-9]{4}'

Is slightly more compact but gives you exactly the same thing. Since the user id is the first field in the password file you could simply do:

Code:

egrep '^[A-Za-z]{2}[0-9]{4}:' /etc/passwd

LinuxRacr · #7 (**permalink**) 08-24-2007

Code:

egrep '^[A-Za-z]{2}[0-9]{4}:' /etc/passwd

Your egrep prints out not only the userids, but the other stuff after the first ":" also. Doesn't work.

Yet another method I found:

Code:

awk -F: '$1~"^[a-z]{2}[0-9]{4}$"{print $1}' /etc/passwd

More UNIX and Linux Forum Topics You Might Find Helpful
Thread	Thread Starter	Forum	Replies	Last Post
Process id's in file names	tekster757	UNIX for Dummies Questions & Answers	1	03-07-2008 12:29 PM
Dowloading a File from FTP Server to a local Server where User Id's are different	ranjith_taurean	Shell Programming and Scripting	1	02-22-2007 07:47 AM
Shell script to return all the ID's from file based on the distribution ID search	kumbhatalok	UNIX for Dummies Questions & Answers	1	10-06-2006 12:53 PM
User should not be allowed to change passwd	brookingsd	UNIX for Dummies Questions & Answers	3	01-23-2006 12:00 PM
Unix user ID's case-sensitive?	dmilleville	UNIX for Dummies Questions & Answers	3	12-14-2003 08:38 PM

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes	Rate This Thread
Switch to Linear Mode Hybrid Mode Switch to Threaded Mode	Rate This Thread:


	Powered by