Why does the wc command count one more character than expected?

Question

The following is the content stored in my file

This is my Input

So, using wc -c command we can get the number of characters stored in the file.

My expected output for above file that edited by using Vim in Ubuntu is 16. But, wc -c command returns 17.

Why is the output like this? There isn't even a carriage return at end of line. So, what is the 17th character?

But, I didn't enter any new line. I just open the vim and enter the content and simply close. I didn't press the enter. — mohangraj, Jul 23 '15 at 10:17
Then vim is a well-behaved editor that automatically adds a trailing newline at the end of the last line in a file. `hexdump -C` your file if you want to see the bytes. — Peter Cordes, Jul 23 '15 at 10:23
Use `od -c` to see the characters in the file including new lines rtc — Ed Heal, Jul 23 '15 at 10:45

score 12 · Answer 1 · edited Jul 31 '21 at 12:42

12

Of course you had enter. Maybe you can't see it. Consider these two examples:

echo -n "This is my Input" | wc -c
16

Because -n is for avoiding enter, but

echo "This is my Input" | wc -c
17

Look at this example too see the new line:

How to see newline?

echo "This is my Input" | od -c

od dumps files in octal and other formats. -c selects ASCII characters or backslash escapes.

And here is an example for file and usage of od:

edited Jul 31 '21 at 12:42

mkrieger1

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answered Jul 23 '15 at 10:17

Fattaneh Talebi

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echo "This is my Input". Ok. In this line, you have enter or not – mohangraj Jul 23 '15 at 10:20
in this case you have enter – Fattaneh Talebi Jul 23 '15 at 10:21
but with -n you don't have enter – Fattaneh Talebi Jul 23 '15 at 10:21
where. It is just a string literal. Is it right or not – mohangraj Jul 23 '15 at 10:23
at the end of the string you have an enter too – Fattaneh Talebi Jul 23 '15 at 10:24
2

Not really. Consider `foo="This is my input"`. The string has no newline in it, BUT if you try to count its charaters with `echo "$foo" | wc -c`, a newline is added by the `echo` command. To count characters in a string in bash, use `${#foo}`. – ghoti Jul 23 '15 at 10:28
I added an image look at to see the newline – Fattaneh Talebi Jul 23 '15 at 10:28
Ok. Here '\n' is added by echo.So, the output is 17. If We pass the input through file like "wc -c a.txt" – mohangraj Jul 23 '15 at 10:33
@Edheal had a perfect comment for you post: echo "This is my Input" | od -c try it to see the newline – Fattaneh Talebi Jul 23 '15 at 10:54
1

@FattanehTalebi I didn't say that is wrong. That's right. My question is "wc -c a.txt". The output is 17. But, the expected output is 16. I am also using the following method. od -c a.txt. At that time it shows only 16. Here, the '\n' is not added. So, why the wc shows 17. what is the extra one character. It is from file or '\n' which we type to execute the command in terminal. – mohangraj Jul 23 '15 at 11:06
@mohanraj oh I got what you mean, ok I'll check it – Fattaneh Talebi Jul 23 '15 at 11:07
@FattanehTalebi Please come out from echo and try to understand my problem. The following is the output for my file if we use od. And Here, there is no '\n'. $ od -c b.txt 0000000 T h i s i s m y i n p u t 0000020 $ – mohangraj Jul 23 '15 at 11:26
@mohanrajl, sorry I couldn't find any answers. – Fattaneh Talebi Jul 23 '15 at 11:45

score 1 · Answer 2 · edited Jul 31 '21 at 12:44

In Linux, when Vim saves buffers, it will terminate every line by appending line terminator of new line.

You can open your file and input :!xxd to view hex-dump or directly use hexdump yourfile command.

0000000: 5468 6973 2069 7320 6d79 2049 6e70 7574  This is my Input
0000010: 0a                                       .
~                                                                                                                                 
~                                                                                                                                 
~

In there you can see, the file have appended 0a in the end of file.

So when you use wc -c to get the number of this file, it will return 17 that includes the new line symbol.

score 0 · Answer 3 · edited Jul 31 '21 at 12:46

0

The input string you are giving as input has no enter/new line, but echo is assigning enter/newline to it. And wc -c reads enter or newline from given by the echo command.

For example

echo k | wc -c

returns 2 because 1 for k and 1 for new line appended by echo.

While

echo -n k | wc -c

returns 1 because -n suppresses the newline.

But wc -c always reads newline.

You can try

printf k | wc -c

It returns 1.

See what it does in file:

bash-4.1$ echo 1234 > newfile
bash-4.1$ cat newfile
1234
bash-4.1$ cat -e newfile
1234$
bash-4.1$ printf 1234 > newfile
bash-4.1$ cat newfile
1234bash-4.1$ cat -e newfile
1234bash-4.1$

edited Jul 31 '21 at 12:46

mkrieger1

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answered Jul 23 '15 at 10:24

Shravan Yadav

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But, I pass the input through file only. like "wc -c a.txt" – mohangraj Jul 23 '15 at 10:28
1

okay try this. echo "This is my Input" > a.txt then run wc -c a.txt and printf "This is my Input" > a.txt and then wc -c a.txt. You know the difference I am talking about. – Shravan Yadav Jul 23 '15 at 10:32
Iam using ubuntu. Editor is vim – mohangraj Jul 23 '15 at 10:33
I am using Linux and shell is ksh and editor vi. You can test this on command prompt.run echo "My" , in output you will get next prompt in newline and run echo -n "My" or printf "My" , in output you will get prompt just after the My string. – Shravan Yadav Jul 23 '15 at 10:36

score -1 · Answer 4 · edited Feb 07 '20 at 10:50

-1

You have 17 because of the /0 chaeracter.

edited Feb 07 '20 at 10:50

BuZZ-dEE

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answered Dec 02 '15 at 14:51

Helper

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You have a couple of typos here `/0` instead of `\0` and `chaeracter` versus `character`. The extra character being counted by **wc -c** isn't a null (`0`) it's a line terminator, likely a `\n`. In a DOS formatted file you'd get 18 because it would be a two byte line terminator `\r\n`. – Alain O'Dea Dec 02 '15 at 15:00

Why does the wc command count one more character than expected?

4 Answers4

How to see newline?

Linked

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