[SOLVED] Count number of lines of a file and comparing

Issue

I need to count the number of lines in a file and then send a message depending if the number of lines is less than or equal to 20. I am trying to do it this way:

touch file.txt
echo "hello" > file.txt
nr_lines = $(wc -l < file.txt)
if[$nr_lines -le 20]; then
  echo "number of lines is less than 20."
fi

But it does not work. What am I doing wrong?

Solution

You are doing a lot right! There are just a few syntax errors in your code that make it not work.

1. Bash does not like spaces in variable assignments
   • Changed nr_lines = $(wc -l < file.txt) to nr_lines=$(wc -l < file.txt)
2. Bash LOVES spaces when it comes to boolean operators though! :)
   • Changed [$nr_lines -le 20] to [ $nr_lines -le 20 ]

touch file.txt
echo "hello" > file.txt
nr_lines=$(wc -l < file.txt)
if [ $nr_lines -le 20 ]; then
  echo "number of lines is less than 20."
fi

When things in bash don't work the silly syntax errors are often:

• Add/Remove spaces somewhere
• Mixup with ' and " and `
• Forgot to escape a special character

Answered By - Lenna

Answer Checked By - Senaida (WPSolving Volunteer)