How to do it...

Using the data obtained by recursively crawling the Packt Publishing website, we can see that inside of www.packtpub.com the entire website is available. Wow! We also created some test data directories and files.

1. Next, open up a terminal and create the following script:

#!/bin/bash

# Let's find all the files with the string "Packt"
DIRECTORY="www.packtpub.com/"
SEARCH_TERM="Packt"

# Can we use grep?
grep "${SEARCH_TERM}" ~/* > result1.txt 2&> /dev/null

# Recursive check
grep -r "${SEARCH_TERM}" "${DIRECTORY}" > result2.txt

# What if we want to check for multiple terms?
grep -r -e "${SEARCH_TERM}" -e "Publishing" "${DIRECTORY}" > result3.txt

# What about find?
find "${DIRECTORY}" -type f -print | xargs grep "${SEARCH_TERM}" > result4.txt

# What about find and looking for the string inside of a specific type of content?
find "${DIRECTORY}" -type f -name "*.xml" ! -name "*.css" -print | xargs grep "${SEARCH_TERM}" > result5.txt

# Can this also be achieved with wildcards and subshell?
grep "${SEARCH_TERM}" $(ls -R "${DIRECTORY}"*.{html,txt}) > result6.txt
RES=$?

if [ ${RES} -eq 0 ]; then
  echo "We found results!"
else
  echo "It broke - it shouldn't happen (Packt is everywhere)!"
fi

# Or for bonus points - a personal favorite
history | grep "ls" # This is really handy to find commands you ran yesterday!

# Aaaannnd the lesson is:
echo "We can do a lot with grep!"
exit 0

2.  If you remain in your home directory (~/) and run the script, the output should be similar to the following:

$ bash search.sh; ls -lah result*.txt
We found results!
We can do a lot with grep!
-rw-rw-r-- 1 rbrash rbrash 0 Nov 14 14:33 result1.txt
-rw-rw-r-- 1 rbrash rbrash 1.2M Nov 14 14:33 result2.txt
-rw-rw-r-- 1 rbrash rbrash 1.2M Nov 14 14:33 result3.txt
-rw-rw-r-- 1 rbrash rbrash 1.2M Nov 14 14:33 result4.txt
-rw-rw-r-- 1 rbrash rbrash 33 Nov 14 14:33 result5.txt
-rw-rw-r-- 1 rbrash rbrash 14K Nov 14 14:33 result6.txt