documenting my notes

grep_notes_1.txt

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+This grep or egrep(just grep with no -E flag), will return all sentences that begin with a capital letter and are followed by any 
+number of uppercase letters, followed by lower case letters, followed by blank spaces and end with a period.
+This is an example of an extended regular expression, which allows for the use of the :alpha: :upper: :lower: etc. meta search criterion.
+
+The '' delineates the beginning of an expression so that the meta characters are not interpreted by bash as commands.
+The carat symbole ^ represents that the beginning of the expression MUST begin with, in this case an uppercase character.
+It is encapsulated by two square brackets [[]] so as to delineate as ingle character, which then MUST be followed by ANY
+number of uppercase characters, lowercase characters, and empty space characters, the ANY condition is inputted by the asterix * metacharacter
+
+The backslash breaks us out of extended regular expressions and then returns us to LITERAL or BASIC regular expressions. In this case
+we MUST follow it by a literal period .
+
+We then ask it to search the lorem.txt using the regular expression, which will give us (roughly) every sentence within the text.
+Note that this is FAR from perfect however, you can even see its major issues by using the same command on this document instead of lorem.txt
+
+##########################################################
+
+grep -E '^[[:upper:]][[:upper:][:lower:] ]*\.' lorem.txt
+
+##########################################################
+
+
+
+some text unique to grep2(compare these two files using the comm and diff(-u) commands)
+
+##########################################################
+
+(this file was copied from grep 1, and originally showed 'unique to grep1' above, it was then passed through the diff command thusly:
+
+##########################################################
+
+diff -Naur grep_notes_1.txt grep_notes_2.txt > grep_patch.txt
+
+##########################################################
+
+This created a grep_patch.txt file that you can see logs the output of the diff command, using the patch command, we can pass this
+file through the command to update our original grep_notes_1.txt file to change ONLY what is different from the two files.
+In this case, grep_notes_2.txt is considered the UPDATED file, and will thusly change the grep_notes_1.txt file.  It could just as easily
+be used to DOWNGRADE the file by reversing the order.  This is useful for software development/updating/downgrading versions of programs.)
+
+##########################################################
+
+patch < grep_patch.txt
+
+Outputs$:patching file grep_notes_1.txt
+##########################################################