I have a regular expression question. Currently, I am running the following command to get a list of all users on my box. How can I modify the following script to exclude users: group1, group2, group3.... I know I need to pipe it into grep, but I am unsure if this is a good approach?

You can do this in a number of ways.

But first, let's be clear about the filtering criteria. In the output of "ls -l", you have fields for file owner and for the group. Which field do you want to act on? The best thing is to post a sample output and tell us which lines you would like saved. Also, do you want to whole content of ls -l, or just the file name?

The number of fields I get back from ls -l, I am throwing into a php array with exec(), and then taking what I need from the array to write a listing. If it is possible I only need user and group.

Current Output:

drwxrwx--x 19 user1 user1 4096 Jul 3 2007 user1
drwxrwx--x 6 user2 user2 4096 May 8 22:56 user2
drwxrwx--x 4 fname1.lname1 fname1.lname1 4096 Jul 10 20:42 fname1.lname1
drwxrwx--x 4 group1 group1 4096 Oct 23 2007 group1
drwxrwx--x 3 group14 group14 4096 Oct 23 2007 group14
drwxrwx--x 3 group15 group15 4096 Oct 23 2007 group15
drwxrwx--x 3 group16 group16 4096 Oct 23 2007 group16
drwxrwx--x 3 group17 group17 4096 Oct 23 2007 group17
drwxrwx--x 3 group18 group18 4096 Oct 23 2007 group18
drwxrwx--x 3 group19 group19 4096 Oct 23 2007 group19

Our conventions changed about a year ago, so I have a mix of users on the system, some with the fname.lname and some with finitiallastname.

I would love my output to look like this:

user1 user1
user2 user2
fname1.lname1
fname2.lname2

I want to exclude the user's that contain the word group from the output.

If all of your "real user" IDs are greater than 999, try this:ta0kira

ls -l|grep -v group|awk '{print $3 " " $4}'

note that in your example output you've got the username and group for the 1st 2 lines, but only the username for the 2nd 2 lines. Seems inconsistent.

What is grep -v group for? Do you sub something in for group?
ta0kira

edit:
Nevermind. Stupid question now that I look again. I was thinking it was supposed to be universal.

Hey Chris,

It is an editted post. I did not want to post student data in my post... I will post one with users who are fake to make it easier to work with. I am trying to get only the users who do NOT have group within their username.

So I would want the following out of this from the regular expression:

root
dutchukm
desrochersm
doddg
farmerer

Can I grep and only show things that do not contain group (this is within the username, not actual group)?

Like ls -l /home | grep --someswitch "group"?

Cheers,

Brent

My point was some of your example reqd output had username & groupname, some only had username.
If you only want usernames output and only want to check usernames, then

ls -l|awk '{print $3}' |grep -v group

ie list files (long format), grab only usernames, ignore usernames containing string 'group'

BTW, usually in Linux ls -l is aliased to ll, so I'd use

ll|awk '{print $3}' |grep -v group

for conciseness

But since the original goal was to get a list of users, the approach of ta0kira seems to be more suitable.

Thanks Everyone,

Your solutions worked like a charm, I ended up using:

ls -l /home | awk '!/group/ {print $3; }'

Now to make php like it

Cheers,

Brent