Awk只能打印整行； 无法访问特定字段

Question

I am currently working on my capstone project for Unix OS I. I'm very close to finishing, but I'm stuck on this part: basically, my assignment is to create a menu-based application wherein a user can enter a first and last name, I take that data, use it create a user name, and then I translate it from lowercase to uppercase, and finally store the data as: firstname:lastname:username .

When asked to display the data I must display it based on the username instead of the first name, and formatted with spaces instead of tabs. For example, it should look like: username firstname lastname . So, I've tried multiple commands, such as sort and awk, but I seem to be only able to access the fields in the file as one big field; eg when I do awk '{print NF}' users.txt to find the number of fields per row, it will return 1, clearly showing that my data is only being entered as one field, instead of the necessary 3 I need. So my question is this: how do I go about changing the number of fields in the text file? Here is my code to add the firstname:lastname:username to the file users.txt:

userInfo=~/capstoneProject/users.txt
#make sure strings is not empty before writing to disk
if [[ "$fname" != ""  &&  "$lname" != "" ]]
then    #write to userInfo (users.txt)
echo "$fname:$lname:$uname" | tr a-z A-Z >> $userInfo
#change to uppercase using |
fi

Is it because of the way I am entering the data into my file? Using echo "$fname:$lname:$uname" ? Because this is the way my textbook showed me how to do it, and they had no trouble later on when using the sort function with specific fields, as I am trying to do now. If more detail is necessary, please let me know; this is the last thing I need before I can submit my project, due tonight.

Answer 1

您的输入文件具有:分隔的字段，因此您需要告诉awk：

awk -F':' '{print NF}' users.txt