"As you can see, awk prints out the first and third
fields of the /etc/passwd file, which happen to be the username and
uid fields respectively. Now, while the script did work, it's not
perfect -- there aren't any spaces between the two output fields!
If you're used to programming in bash or python, you may have
expected the print $1 $3 command to insert a space between the two
fields. However, when two strings appear next to each other in an
awk program, awk concatenates them without adding an intermediate
space. The following command will insert a space between both
fields:"