Parsing .csv file in bash, not reading final line

Question

I'm trying to parse a csv file I made with Google Spreadsheet. It's very simple for testing purposes, and is basically:

1,2
3,4
5,6

The problem is that the csv doesn't end in a newline character so when I cat the file in BASH, I get

MacBook-Pro:Desktop kkSlider$ cat test.csv 
1,2 
3,4 
5,6MacBook-Pro:Desktop kkSlider$ 

I just want to read line by line in a BASH script using a while loop that every guide suggests, and my script looks like this:

while IFS=',' read -r last first
do
    echo "$last $first"
done < test.csv

The output is:

MacBook-Pro:Desktop kkSlider$ ./test.sh
1 2
3 4

Any ideas on how I could have it read that last line and echo it?

Thanks in advance.

Answer 1

You can force the input to your loop to end with a newline thus:

#!/bin/bash
(cat test.csv ; echo) | while IFS=',' read -r last first
do
    echo "$last $first"
done

Unfortunately, this may result in an empty line at the end of your output if the input already has a newline at the end. You can fix that with a little addition:

!/bin/bash
(cat test.csv ; echo) | while IFS=',' read -r last first
do
    if [[ $last != "" ]] ; then
        echo "$last $first"
    fi
done

Another method relies on the fact that the values are being placed into the variables by the read but they're just not being output because of the while statement:

#!/bin/bash
while IFS=',' read -r last first
do
    echo "$last $first"
done <test.csv
if [[ $last != "" ]] ; then
    echo "$last $first"
fi

That one works without creating another subshell to modify the input to the while statement.

---

Of course, I'm assuming here that you want to do more inside the loop that just output the values with a space rather than a comma. If that's all you wanted to do, there are other tools better suited than a bash read loop, such as:

tr "," " " <test.csv

Answer 2

cat file |sed -e '${/^$/!s/$/\n/;}'| while IFS=',' read -r last first; do echo "$last $first"; done