how to know the number of lines in file in linux code example

Example 1: shell script to count number of lines in a file

echo Enter the filename
read file
w=`cat $file | wc -w`
c=`cat $file | wc -c`
l=`grep -c "." $file`
echo Number of characters in $file is $c
echo Number of words in $file is $w
echo Number of lines in $file is $l

Example 2: linux command to get number of lines in a file

wc -l <filename>
# output = <number of lines> <filename>
# to omit the file name in output
wc -l < <filename>
# output = <number of lines>