Problems Writing Output to File

Question

I am reading in a small csv file in the format size,name - one set per line. For my testing file I have two lines in the csv file.

If I use the code

while
        IFS=',' read -r size name
do
        printf "%s\n" "name"
done < temp1.txt

The name values for each of the lines is printed to the terminal.

If I use the code

while
        IFS=',' read -r size name
do
        printf "%s\n" "name" > temp2.txt
done < temp1.txt

Then only the last name is printed to the temp2.txt file.

What am I doing wrong?!

Answer 1

You are using >, so that the file gets truncated every time. Instead, use >> to append:

So it should be like this:

        printf "%s\n" "name" >> temp2.txt
                             ^^

All together:

while
        IFS=',' read -r size name
do
        printf "%s\n" "name" >> temp2.txt
done < temp1.txt

---

Basic example:

$ echo "hello" > a
$ echo "bye" > a
$ cat a
bye                        # just last line gets written

$ echo "hello" >> a
$ echo "bye" >> a
$ cat a
hello
bye                        # everything gets written