CODEWITHSUNDEEP
bashfile
Simon
Simon

Reputation: 6480

Not empty file, but "wc -l" outputs 0

I have a non-empty file (even a big one, 400Ko), that I can read with less.

But if I try to output the number of lines with wc -l /path/to/file it outputs 0.

How can it be possible?

Upvotes: 4

Views: 2068

Answers (4)

chepner
chepner

Reputation: 531798

You can verify for yourself that the file contains no newline/linefeed (ASCII 10) characters, which would result in wc -l reporting 0 lines.

  1. First, count the characters in your file:

    wc -c /path/to/file

    You should get a non-zero value.

  2. Now, filter out everything that isn't a newline:

    tr -dc '\n' /path/to/file | wc -c

    You should get back 0.

  3. Or, delete the newlines and count the result.

    tr -d '\n' | wc -c

    You should get back the same value as in step 1.

Upvotes: 4

franklinsijo
franklinsijo

Reputation: 18270

It is possible if the HTML file is minified. The newline characters would have been removed during minification of the content.

Try with file command,

file filename.html

filename.html: HTML document text, UTF-8 Unicode text, with very long lines, with no line terminators

Upvotes: 2

agc
agc

Reputation: 8406

Here's one way it's possible. Make a 400k file with just nulls in it:

dd if=/dev/zero bs=1024 count=400 of=/tmp/nulls ; ls -log /tmp/nulls

Output shows the file exists:

400+0 records in
400+0 records out
409600 bytes (410 kB, 400 KiB) copied, 0.00343425 s, 119 MB/s
-rw-rw-r-- 1 409600 Feb 28 11:12 /tmp/nulls

Now count the lines:

wc -l /tmp/nulls
0 /tmp/nulls

Upvotes: 2

vim_
vim_

Reputation: 2170

wc counts number of '\n' characters in the file. Could it be that your file does not contain one?

Here is the GNU source: https://www.gnu.org/software/cflow/manual/html_node/Source-of-wc-command.html

look for COUNT(c) macro.

Upvotes: 3

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