Couting the number of blank lines in a file

Counting the number of blank lines in a file.

Here are a few ways to count the number of blank lines in a file using shell scripting.

Assume we have a file named test which has the following contents :

The best way to make your dreams come true is to wake up Modest doubt is called the beacon of the wise We're all just walking each other home Make no judgments where you have no compassion You must be the change you wish to see in the world Love is the way messengers from the mystery tell us things In order to learn the art of dying , one must know completely the art of living A poem should not mean. But be Love all, serve all, feed all If you want to be a rebel, be kind

Note that the above file has 10 blank lines includin the one at the end. Let see how we can count the same using commands or scripts

1. Using grep :

grep -c ^$ test 10

When -c option is used with grep, it counts the number of occurrences of the search string and outputs the same. 2. Using awk:

awk 'BEGIN{ count=0 } /^$/{count++} END {print count}' test 10

Awk reads one line of the file at a time, hence we compare each line with the blank line i.e. ^$ and increment a count whenever there is match and print the final count before exiting.

3. Using shell scripting :

#!/bin/bash if [ $# -lt 1 ] then echo -e "\n INFO : Please pass a file name \n " exit fi if [ $# -gt 1 ] then echo -e "\n INFO: Please pass only one file name \n " exit fi lcount=0 while read lines do if [[ $lines =~ ^$ ]] then echo $line ((lcount++)) fi done < $1 echo "$lcount"

Save the script as line_count.sh . Give it execute permission using

chmod 777 line_count.sh

And then execute it

./line_count.sh test 10

The above script uses a while loop to pass through the file, one line at a time and on reading each line an "if" statement is used to comapre the line with the blank line. Note the use of double [ with the if statement. A single [ will not be able to interpret the regular expressions in an if statement. When the comparision is a success a count is incremented and the same is printed at the end.