Friday, October 29, 2010

Halloween

The entire week I spent reading about LPIC. At first I read about the shell. A user's shell is set in /etc/passwd and defaults to bash if it doesn't exist. When a user first logs in the /etc/profile is "sourced" as the book puts it. Can I say call? Call sounds better. We're going with call. Correct me if I'm wrong. So once that is done the bash_profile is called and finally bashrc and if for some reason one of these scripts does not exist it moves onto the next.

I flipped forward a bit and read about Special Characters many of which I know of. Examples are the && which performs a command if the first command succeeded, | pipe which pipes the output to a program, || like and except if the first fails THEN it performs the second, ; which just executes command and finally > and < which pipes the output and input into a program respectively.

I also read about the ps command which like before I have dabbled with but the book has you learn all it's switches. ps basically just gives you a list of processes for the current user. ps -a shows ALL processes. A really neat one if pstree which gives you a tree of processes so you can see what process started what with all beginning at init.

Henry also showed me a bit about kill. As you can guess it kills a process but there are 60 variations. The default kill sends the kill command but gives the process a chance to save, kill -9 kills the program outright, kill -1 restarts the process.

Next part of the chapter is "Managing Process Priorities" and then next chapter is vi. A whole chapter dedicated to vi. I also took one of the books home but I'll have it back tomorrow.