Question

If I create a file in ubuntu like this: “echo “asd” > file.txt” and I do a ls -l file.txt it says that it’s size is 4 bytes, but I only wrote 3 (asd). If I do “cat file.txt” it shows the 3 chars that I have added. Why is the file 4 bytes large?

Answer 1

asd + new line character = 4 bytes

$ echo asd | wc -c
4
$ echo -n asd | wc -c
3
$ echo asd | hd
00000000  61 73 64 0a                                       |asd.|
00000004

-n in echo switches newline off

hd shows you a hexdump of the stream. You see the 0a character at the end. That is the fourth character, newline.