如果文件没有行尾字符，则 wc -l 不计算文件的最后一个

Question

I need to count all lines of an unix file. The file has 3 lines but wc -l gives only 2 count.

I understand that it is not counting last line because it does not have end of line character

Could any one please tell me how to count that line as well ?

Answer 1

grep -c returns the number of matching lines. Just use an empty string "" as your matching expression:

$ echo -n $'a\nb\nc' > 2or3.txt
$ cat 2or3.txt | wc -l
2
$ grep -c "" 2or3.txt
3

Answer 2

It is better to have all lines ending with EOL \\n in Unix files. You can do:

{ cat file; echo ''; } | wc -l

Or this awk:

awk 'END{print NR}' file

Answer 3

This approach will give the correct line count regardless of whether the last line in the file ends with a newline or not.

awk will make sure that, in its output, each line it prints ends with a new line character. Thus, to be sure each line ends in a newline before sending the line to wc , use:

awk '1' file | wc -l

Here, we use the trivial awk program that consists solely of the number 1 . awk interprets this cryptic statement to mean "print the line" which it does, being assured that a trailing newline is present.

Examples

Let us create a file with three lines, each ending with a newline, and count the lines:

$ echo -n $'a\nb\nc\n' >file
$ awk '1' f | wc -l
3

The correct number is found.

Now, let's try again with the last new line missing:

$ echo -n $'a\nb\nc' >file
$ awk '1' f | wc -l
3

This still provides the right number. awk automatically corrects for a missing newline but leaves the file alone if the last newline is present.

Answer 4

Respect

I respect the answer from John1024 and would like to expand upon it.

Line Count function

I find myself comparing line counts A LOT especially from the clipboard, so I have defined a bash function. I'd like to modify it to show the filenames and when passed more than 1 file a total. However, it hasn't been important enough for me to do so far.

# semicolons used because this is a condensed to 1 line in my ~/.bash_profile
function wcl(){
  if [[ -z "${1:-}" ]]; then
    set -- /dev/stdin "$@";
  fi;
  for f in "$@"; do
    awk 1 "$f" | wc -l;
  done;
}

Counting lines without the function

# Line count of the file
$ cat file_with_newline    | wc -l
       3

# Line count of the file
$ cat file_without_newline | wc -l
       2

# Line count of the file unchanged by cat
$ cat file_without_newline | cat | wc -l
       2

# Line count of the file changed by awk
$ cat file_without_newline | awk 1 | wc -l
       3

# Line count of the file changed by only the first call to awk
$ cat file_without_newline | awk 1 | awk 1 | awk 1 | wc -l
       3

# Line count of the file unchanged by awk because it ends with a newline character
$ cat file_with_newline    | awk 1 | awk 1 | awk 1 | wc -l
       3

Counting characters (why you don't want to put a wrapper around wc )

# Character count of the file
$ cat file_with_newline    | wc -c
       6

# Character count of the file unchanged by awk because it ends with a newline character
$ cat file_with_newline    | awk 1 | awk 1 | awk 1 | wc -c
       6

# Character count of the file
$ cat file_without_newline | wc -c
       5

# Character count of the file changed by awk
$ cat file_without_newline | awk 1 | wc -c
       6

Counting lines with the function

# Line count function used on stdin
$ cat file_with_newline    | wcl
       3

# Line count function used on stdin
$ cat file_without_newline | wcl
       3

# Line count function used on filenames passed as arguments
$ wcl file_without_newline  file_with_newline
       3
       3