Searching for a specific username

Red_Templar · 04-27-2015, 05:24 AM

Hey guys,

I've recently started learning Linux, and I was wondering if anyone can tell me how I can search for a specific usernames starting with a certain letter on a Linux system.

For example: How do I get it to display all the usernames starting with a J? (So that it would show me, Jack, Jason, John, etc...)
I tried to find the answer online, but haven't had much luck so far.

joe_2000 · 04-27-2015, 03:29 PM

Quote:

Originally Posted by Red_Templar

Hey guys,

I've recently started learning Linux, and I was wondering if anyone can tell me how I can search for a specific usernames starting with a certain letter on a Linux system.

For example: How do I get it to display all the usernames starting with a J? (So that it would show me, Jack, Jason, John, etc...)
I tried to find the answer online, but haven't had much luck so far.

All usernames are in /etc/password. So you can grep for lines in that file that start with a j in the following way:

Code:

grep -i ^j /etc/passwd

The -i flag is for the pattern matching to be case insensitive
If you want to only output the actual username, pipe that output into cut:

Code:

grep -i ^j /etc/passwd | cut -d':' -f 1

unSpawn · 04-27-2015, 03:58 PM

Quote:

Originally Posted by joe_2000

If you want to only output the actual username, pipe that output into cut

Or use awk?

Code:

awk -F':' '/^j/ {print $1}' /etc/passwd

joe_2000 · 04-27-2015, 04:22 PM

Quote:

Originally Posted by unSpawn

Or use awk?

Code:

awk -F':' '/^j/ {print $1}' /etc/passwd

Don't know why, but for some reason I seem to be bad at remembering the awk syntax. I found that most of times I can get away with pipe and cut.

Maybe I should use awk more often to get better at it. But then, luckily, many ways lead to Rome ;-)

Red_Templar · 04-28-2015, 02:07 AM

Thanks guys, both ways worked great!