Merge pull request #221 from augmentedfourth/master

Add `-C` (context) to list of grep options, since it goes well with `-A` and `-B`

README.md

@@ -63,7 +63,7 @@ Notes:
 
 - Basic network management: `ip` or `ifconfig`, `dig`.
 
-- Know regular expressions well, and the various flags to `grep`/`egrep`. The `-i`, `-o`, `-v`, `-A`, and `-B` options are worth knowing.
+- Know regular expressions well, and the various flags to `grep`/`egrep`. The `-i`, `-o`, `-v`, `-A`, `-B`, and `-C` options are worth knowing.
 
 - Learn to use `apt-get`, `yum`, `dnf` or `pacman` (depending on distro) to find and install packages. And make sure you have `pip` to install Python-based command-line tools (a few below are easiest to install via `pip`).