What's the easiest way to get a user's full name on a Linux/POSIX system?

Question

I could grep through /etc/passwd but that seems onerous. \'finger\' isn\'t installed and I\'d like to avoid that dependency. This is for a program so it would be nice if there

Answer 1

My code works in bash and ksh, but not dash or old Bourne shell. It reads the other fields too, in case you might want them.

IFS=: read user x uid gid gecos hm sh < <( getent passwd $USER )
name=${gecos%%,*}
echo "$name"

You could also scan the whole /etc/passwd file. This works in plain Bourne shell, in 1 process, but not so much with LDAP or what.

while IFS=: read user x uid gid gecos hm sh; do
  name=${gecos%%,*}
  [ $uid -ge 1000 -a $uid -lt 60000 ] && echo "$name"
done < /etc/passwd

On the other hand, using tools is good. And C is good too.