Using `ls` to show real name of file owners

Question

Unix users can have their real names listed in /etc/passwd/. The finger command can display the real names. Can ls -l show these real names of file owners next to the files?

If ls cannot do this directly, then what's the best way to pipe the output of ls -l through finger to achieve this result? Sounds like a job for awk - use ls -l | finger as a lookup table to overwrite the third column of ls -l.

(Related question in case the real names are not in finger but in a lookup table: Lookup-table text replacement in bash)

Answer 1

You can parse ls as @Cyrus mentioned in the comments. However, I suggest a simple script to do that, which you can make as an executable:

while read -r line
do
    user=`echo "$line" | awk '{print $3}'`
    name=`getent passwd "$user" | cut -d ':' -f 5 | cut -d ',' -f 1`
    echo $line | sed "s/$user/$name/"
done < <(ls -lh | tail -n +2)

The user variable gets the username of the owner (from the 3rd column of the ls output), name gets that username's real name, and then in the output of ls we just replace the username with the real name using sed.

I haven't used finger in my example, as parsing the /etc/passwd file is less error-prone and you also do not need an external tool. (finger isn't installed on Debian/Ubuntu by default)

Example output:

-rwxr-xr-x 1 Pavlin Nikolov fanatique 41 Aug 29 15:13 cpu.sh
-rwxr-xr-x 1 Pavlin Nikolov fanatique 193 Aug 28 11:36 httpingwrap.sh
-rwxr-xr-x 1 Pavlin Nikolov fanatique 3.8K Aug 14 15:36 imgconv.py
-rwxr-xr-x 1 Pavlin Nikolov fanatique 504 Oct 19 16:04 lsp
-rwxr-xr-x 1 Pavlin Nikolov fanatique 77 Aug 28 14:24 mg
-rwxrwxrwx 1 Pavlin Nikolov fanatique 386 Sep 14 15:02 mon-install.sh
-rwxr-xr-x 1 Pavlin Nikolov fanatique 589 Sep 11 11:55 ping-wrapper.py

Note that it is not the best-looking output, as it is not aligned perfectly, but it should still work.