Refreshing Drink of Ideas

Linux / Unix Notes

This article is a list of notes I've collected to help me with Linux and/or Unix.  Please don't consider this a comprehensive reference.  I'm not a Linux or Unix expert.  These notes are just some things I've had to remember but always seem to forget when I've had to log onto a Linux or Unix machine for the following:
  • Setting up a website.  I think Linux is the easiest platform and has the most tools, free and open, readily available.
  • Attempting to develop an application for my Android phone (which uses a form a Unix) and experimenting with root access with a command prompt.
  • Hacking my older Directv Tivo DVR
I've never tried or even had much interest in using Linux and X11 windows as an alternative to MS Windows for my desktop.  So there won't be any notes about that in this article.

There are certainly more comprehensive and accessible Linux/Unix references out there on other websites.  However, because there were some things I couldn't find quickly enough or expressed simply enough or whatever, I found I needed to write my own notes.  These notes are now here where I can find them no matter where I am.  They are also for anybody else, due to being in the same situation for frame of mind as me, has Googled here for the quickest answer.

Wherever I list a shell command, the shell will most likely be Bash with a prompt of "$".   The commands can be used interactively from a terminal or from within a shell script.  Here are the notes below.


Display which shell processor is being used to interpret your commands at the command line:
$ echo $0
The above will echo out the name of the shell.  For example the output may be:
-bash
Alternatively to get the full path to the shell processor, do the following:
$ echo $SHELL

Listing the contents of a directory

$ ls
List each item with full attributes
$ ls -l

To list even files that begin with "." because these are normally hidden
$ ls -l -a

To list files that begin with "." but excluding the implied directory names of "." (current) or ".." (parent)

$ ls -l -A

A file name or directory name, with or without wildcards ('*" or "?"), may be be provided to get directory limited to files or directories that match. 

$ ls -l -A <filename>

If shell is set up for it (Bash usually is), then the easier to remember "dir" command can be used

$ dir -l -A

For quick help on any command, try including "--help" option:

$ dir --help

For extensive help (when available) use the "man" command:
$ man set
The above command will list out a manual article on the "set" command


Displaying the current directory (or working directory):
$ pwd

Changing the current directory - for example, to a directory called "public_html" under the current:
$ cd  public_html
A wildcard will make this quicker and easier to type if "public_html" is the only directory that begins with "pub"
$ cd pub*

To make a new subdirectory:
$mkdir <directory name>

The Bash shell can show the host name and current directory in each prompt.  This is the default on many Linux systems.  Set variable PS1 as follows:
$ PS1="\u@\h:\w\$"
Variable PS1 defines the prompt string for Bash.  With special escape character "\" commands cause system values to be inserted.  A good explanation for this was found at on the web here.


Changing the terminal type that system expects you to have
Just set the TERM variable
$ TERM=vt100

Listing all variables with their values
$ set

Exporting variables to sub-processes:
The first command will cause all subsequently created or modified variables to be exported
$ set -a
The next command will specify a list of names to export
$ export <names>

Start a background process
In the below example, the "&" indicates that the given command has a requirement for terminal access
$ <command> &

List running processes
The following will list all processes user is allowed to view based on authorization level
$ ps -e
A root user would be able to see all processes running on the system with the above.  A non-privileged user would only be able to see his own.

Use --help to see more options.


Execute a command as another user

This is may be allowed only if a privileged user.  Also may prompt for password. 

su -c "<command>" <userid>

Sending the output of one command to be processed by another, use the pipe character "|".   The standard output of 1st (normally printed on terminal display) of will be sent as the standard input (normally from terminal keyboard) to the 2nd.

Example using grep processor to list out any running process that contains a certain string ("bash") in its name

$ ps -e | grep "bash"

To control flow of output to the screen
Pipe output to "more" processor
$ set | more
The above list all variables ("set") by sending one page of output to the terminal at a time.  Key "q" or cntrl-c to stop.  Any other key will go to next page.

A better processor to use is "less"
$ set  | less
The above will list all variables by 1st sending 1st page of output to the terminal.  The "q"  key will stop.  Keyboard up and down arrow keys will allow navigating up and down one line at a time.  Space key will move a page at a time.  Other keys may do other things so look this up in "man" or use
$ less --help

Forthstar - clock 23:55:27 - Saturday, 24.04.10 - Linux / Unix - 6042311x - pencil permalink
Karma points: 8420. Do you like this article? [yes/no]

RSS 2.0 feed, Trackback, print preview, email this article

  • RSS 2.0 feed of this article, including comments:  RSS 2.0 comments feed
  • Use this Trackback URL for ping (right mouse click and copy URL).
  • You can [print] this article, [email] it, or export a [PDF].

Local search Linux Unix Notes

No results found or search not configured.

Google search

No results found or search not configured.

Add new comment:

Comments must be approved before being published. Thank you!

Preview and Confirm Your Comment!

<img>http://i.imgur.com/nRlegBm.png</img>

JUST GRAB CASTLE CLASH RESOURCES!

Nevertheless due to the hard truth that 80% of the players of Castle Clash most often aren’t anything but casual video gamers. the limit in each day for each resources is 1000. Use only our tool to be safe! the good news is that Castle Clash Hack Android is now available for android user. you’d be required to have A lot knowledge of coding. . you can collect gems, where you have to pay to download a cheat that doesn't even work. PC, This way, You can also buy soldiers and weapons to beat other players with the help of the codes. building troops and much more. PC, It is a very rare opportunity that should not be ignored at any cost. Developed to be played with an internet connection, This tool will hack Castle Clash game and get some resources as you need and send it to your personal account. Though it is true that the levels and gems are expensive to buy to move forward in the game, Mana and Gems is free among the many gamers. It is fully compatible with both Android and iOs versions of Castle Clash. You can download castle clash hack from this websites to avail these bonus points without spending anything on them.
hack castle clash tren android
castle clash hack facebook
castle clash merits glitch
castle clash free gems no survey or download
castle clash online hack no survey video
castle clash cheat apk
castle clash hack ipod
cheat castle clash july 2014
castle clash hack honor badges
castle clash hack for ios
castle clash unlimited gems iphone
castle clash hack january 2015
castle clash hack serial key
castle clash v4.11 cheats rar
castle clash 1000 gems
castle clash best way to get free gems
castle clash link 400 gems
castle clash hack glitch
hack castle clash android download
castle clash cheat 2014
castle clash cheat gems
hack castle clash in android
castle clash raid glitch
castle clash unlimited gems offline apk
castle clash cheat for legendary heroes
Cheat Castle Clash Di Bluestacks. Castle Clash Hero GeneratorCastle Clash Gems Hack Cydia. Castle Clash Hack V5.3 Unlimited Gems Gold And ManaCastle Clash Glitch 2016. Cheat Castle Clash ComputerCastle Clash Hack 3.0. Castle Clash Hack - Gold Mana GemsDownload Free Gems For Castle Clash. Castle Clash Cheat Bahasa Indonesia
castle clash hack license key
castle clash gem roll hack
castle clash cheat v2.0 activation key
castle clash raid glitch
cheats for castle clash without computer
castle clash hack glitch
castle clash online hack tool 2014
cheat castle clash tools
castle clash hack v5.1
castle clash gems hack pc
cheat engine castle clash pc
castle clash hack here be monsters
castle clash rolling 50000 gems
castle clash unlimited apk 1.2.52
castle clash best way to get free gems
hack castle clash v1.2.1
castle clash lost realm glitch
castle clash hack cheat
castle clash challenge glitch
cheat engine 6.2 castle clash gems
cheat castle clash 2014
castle clash hack password generator
castle clash online generator no survey 1.15
castle clash cheat root
castle clash hack download without survey
Cheat Castle Clash 1.2.26. Castle Clash Unlimited Shards HackCastle Clash Gem Generator No Download No Survey. Castle Clash Cheat Ohne DownloadCheat Castle Clash Terbaru. Glitch De Castle ClashCastle Clash Gems Over Time. Hack Castle Clash Android FreeCastle Clash Hero Generator. Hack Gems Castle Clash 1.2.61

Spam control