How to count the total number of lines in multiple files using a bash script

Method 1
awk 'END {print NR}' *.java

Method 2
wc -l *.php

For windows Command line:

for %G in (*.sql) do find /c /v "_+_" %G

For linux Command Line:

wc -l *.sh

Method 3
cat *.java | wc -l

Method 4
Using find to generate a list of files, useful when files are in sub directories.

wc -l `find -name '*.java'`