count lines in a file

Question

I'm sure there are many ways to do this: how can I count the number of lines in a text file?

$ <cmd> file.txt
1020 lines

Answer 1

The standard way is with wc, which takes arguments to specify what it should count (bytes, chars, words, etc.); -l is for lines:

$ wc -l file.txt
1020 file.txt

Answer 2

Steven D forgot GNU sed:

sed -n '$=' file.txt

Also, if you want the count without outputting the filename and you're using wc:

wc -l < file.txt

Just for the heck of it:

cat -n file.txt | tail -n 1 | cut -f1

Answer 3

As Michael said, wc -l is the way to go. But, just in case you inexplicably have bash, perl, or awk but not wc, here are a few more solutions:

Bash-only

$ LINECT=0; while read -r LINE; do (( LINECT++ )); done < file.txt; echo $LINECT

Perl Solutions

$ perl -lne 'END { print $. }' file.txt

and the far less readable:

$ perl -lne '}{ print $.' file.txt

Awk Solution

$  awk 'END {print NR}' file.txt

Answer 4

Word of warning when using

wc -l

because wc -l functions by counting \n, if the last line in your file doesn't end in a newline effectively the line count will be off by 1. (hence the old convention leaving newline at the end of your file)

Since I can never be sure if any given file follows the convention of ending the last line with a newline or not, I recommend using any of these alternate commands which will include the last line in the count regardless of newline or not.

sed -n $= filename
perl -lne 'END { print $. }' filename
awk 'END {print NR}' filename
grep -c '' filename

Answer 5

You can always use the command grep as follows:

grep -c "^" file.txt

It will count all the actual rows of file.txt, whether or not its last row contains a LF character at the end.

Answer 6

In case you only have bash and absolutely no external tools available, you could also do the following:

count=0
while read
do
  ((count=$count+1))
done <file.txt
echo $count

Explanation: the loop reads standard input line by line (read; since we do nothing with the read input anyway, no variable is provided to store it in), and increases the variable count each time. Due to redirection (<file.txt after done), standard input for the loop is from file.txt.

Answer 7

If you're looking to count smaller files a simple wc -l file.txt could work.

Looking for an answer to this question myself, working with large files that are several gigs, I found the following tool:

https://github.com/crioux/turbo-linecount

Also, depending on your system configuration--if you're using an older version of wc you might be better off piping larger chunks with dd like so:

dd if={file_path} bs=128M | wc -l

Answer 8

grep -c $ is very simple and works great.

I even saved it as an alias since I use it a lot _{^{(lc stand for line count)}}:

alias lc="grep -c $"

It can be used either this way:

lc myFile

Or that way:

cat myFile | lc

Note that this will not count the last line if it is empty. For my uses that is almost always OK though.