rust book I/O project follow along
the program will check for the environment variable CASE_SENSITIVE.
If this environment variable exists, then the program will only print out strings that match exactly what you enter.
Otherwise it will print out anything that matches the entered string.
The format to run is minigrep QUERY FILENAME where QUERY is the query string to look for
and FILENAME is the file to look in it for. FILENAME follows POSIX dir structure so you can run this program using
absolute or relative path names.
CASE_SENSITIVE=1 ./minigrep Pick testfiles/test.txt
will search for Pick in the test.txt file in the testfiles directory
relative to the current working directory. Since the CASE_SENSITIVE environment variable was set, the query will be case
sensitive.