grep oneliner: search for a value recursively

Ever forget exactly which file you had placed some particular code in and really wanted to find it quick. Here's a grep oneliner to do just that. In this example, I am looking for "#define MAX_VALUE" in a directory containing many source files and sub-directories.
grep -R --include "*.c" "#define MAX_VALUE" .


Note: the "." indicates the current directory in Linux. If your files are in a different tree, just replace the "." with that tree's root location. For example, if you wanted to look /usr/bin/local/:

grep -R --include "*.c" "#define MAX_VALUE" /usr/bin/local

for oneliner - make backups in a directory

Create a backup copy of all filenames of a specific extension:

for f in *.c; do cp $f $f.c.backup; done

This will find all "c" files in the current directory you are in and then make a copy of them, appending ".backup" to the end of the original filename.

Simple, and maybe overused....yet so nice to use sometimes when pushing around a lot of files.

sed oneliner - replace text in file

One liner for use inside of a script where a line, or part of a line, or a file needs to be changed:


Suppose that we are passing the name of a file to edit to this script as the first parameter


OLDVARIABLE="the old variable"
NEWVARIABLE="the new variable"
...
sed -i "s/$OLDVARIABLE/$NEWVARIABLE/" $1

This will do an in place (-i) edit of the file passed to the sed script (the first parameter $1). The sed script itself will do a substitution (s) of the first instance of OLDVARIABLE with the value of NEWVARIABLE. If you wanted to do this at every instance, add (g) to the end of the sed script /g"
The double qoutes around the sed script are not a typo...they are there because I am using variables instead of text or regex.
And that's my oneliner for today...snuck it right in before midnight.

July Gifts

My birthday is this month and I realized that not only am I getting a little older but it's been some time since I really posted on here. So, amidst a book review I am working on, family, school, an IEEE standard, and hopefully fishing, I have decided to try something new....but not really unique.
For the month of July, I want to try to post some useful oneliner script or small code block that I find helpful. I think I am going to start with some sed or awk love....but there are probably 8 billion of those on the net. I will think about while I dream of packets, beer, babes, and the beach. LOL

Updated my certs --- GSNA and MCTS

This last week I reviewed and sat the GSNA and the MS70-643 (which I was certain that I would fail). I ended up falling asleep in the GSNA and passing with 86%. Next time it'll be above 90% though. I was surprised at the 70-643. I took it cold a few months ago and bombed it...I think my score was just under 500. That was my first ever MS test experience and for some reason I thought the CISSP experience was more pleasant. In any event, I earned an 890 on that exam.
I had initially bought the vouchers (a 2-pack) for my previous job. However, I don't really need any MS certs now for where I am (Back in packet analysis heaven!!!!!). I do have another voucher out of the pack I bought, so I'll have to se that one. After that, maybe the full MCITP.
But I want to really look into is the SANS GSE or Cyber Guardian programs, the GREM, GCIH, and GCFA. Those sound like fun. Some linux ones would be cool too.
I realize that I like the certs. Not for my resume or my wall...but for my own sense of accomplishment. I mean let's face it, only the person sitting the exam knows for sure how much knowledge they had and how much brain-dump help that they had in passing. I like to learn new things, and expanding my skillset and then proving to ME that I learned something....I like that!!!

I even made a picture: