5 ways to count the lines of a file in Linux

There are multiple ways to count the number of lines of a file in Linux. In our daily life we need to count number of lines of a csv file, text file etc and the most popular command we use "wc -l". In this article i will show you 5 different ways to find number of line along with wc -l

Let us consider we have 2 sample file name as sample1.txt and sample2.txt which having 10 and 3 lines as following. I will show you different examples to get the number of lines.

Contents of sample1.txt

[~]$ cat sample1.txt

One
Two
Three
four
five
six This is longest line
seven
eight
nine
ten

Contents of sample2.txt

[~]$ cat sample2.txt
One
Two Longest Line
Three

The wc (word count) command is very popular in Unix/Linux to find number of lines count, word counts, byte and characters count in a file. The syntax of wc command is as following.

wc  [OPTION]... [FILE]...

Where OPTION are as below:

  -c, --bytes            print the byte counts
  -m, --chars            print the character counts
  -l, --lines            print the newline counts
      --files0-from=F    read input from the files specified by
                           NUL-terminated names in file F;
                           If F is - then read names from standard input
  -L, --max-line-length  print the length of the longest line
  -w, --words            print the word counts

[~]$ wc sample1.txt sample2.txt

10 14 70 sample1.txt
 3  5 27 sample2.txt
13 19 97 total

In the above example first column shows number of line , 2nd column shows words and 3rd column shows number of chars. Last row shows the total counts of all files.

Lets us have a look of different ways to find the number of lines in a file , we will use sample1.txt in our demo.

1) Counting lines with WC command

[~]$ cat sample1.txt | wc -l
10

or

[~]$ wc -l sample1.txt
10 sample1.txt

2) Counting lines with sed command
sed uses "=" operator for line numbering and "$" gives the last count of numbering which is total number of lines.

[~]$ sed -n "$=" sample1.txt
10

3) grep command with -c option:

To count all non-empty lines or non-blank line.

[~]$ grep -c "." sample2.txt
3

To count all line including blank or empty lines.

[~]$ grep -c ".*" sample2.txt
4

or

[~]$ grep -c "^" sample2.txt
4

4). Counting line with awk:

awk with NR variable gives the line numbers and by printing NR with the end block it gives the line number of the last line which is nothing but a total number of lines in file.

[~]$ awk 'END {print NR}' sample1.txt
10

5). Counting lines with perl:

End block as in awk we can use also with perl. In Perl "$." gives the number of lines.

[~]$ perl -lne 'END {print $.}' sample1.txt
10

Note:

To find the longest line character count we can use wc with -L option. As shown below in sample1.txt file the longest line having 24 character where as in sample2.txt it is 16.

[~]$ wc -L sample1.txt sample2.txt
24 sample1.txt
16 sample2.txt
24 total

Have a look on couple of heck of counting lines.

Trick 01:

cat -n sample1.txt | tail -n 1 | cut -f1

Explanation : "cat -n sample1.txt" keeps a number line in file and pipe "tail -n1" gives the first row from bottom which includes line number and last line content. Then pipe "cut -f1" take out the first field of last line(last line number) which is nothing but the total count of lines.

Trick 02:

Using the while loop reading file line by line and increasing counter.

#!/bin/bash

count=0
while read
do
  ((count=$count+1))
done <sample1.txt

echo $count

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