Tag Archives: console

‘bash’ A.K.A. The Solution for Everything – Bourne Shell as per v7 Unix to Today’s

In 1979 Unix v7 started being distributed with the original Bourne Shell. Simply, it’s a program that sits at /bin/sh and runs in the terminal. You may ask, “what’s the difference between a shell and the terminal?” Let’s cover that right now, because it’s something that routinely isn’t common knowledge, but it really ought to be as it sets the basis for understanding a lot of what is going on in Unix based systems (that includes almost every practical system on a PC, Server, in the cloud, on your phones, and more. Probably easiest to explain it simply as everything that isn’t the Microsoft Windows OS)

A Shell and the Terminal

Terminal – A terminal is the text input and output environment on the system.

Shell – This is the command line interpreter that is run at the terminal.

Another point of context, is that a terminal, shell, and the word console are all used in various ways and sometimes interchangeably. However, these words do not mean the same thing at all. They are distinct individual parts of the system. For example, console, which is used in a strangely disingenuous way all over Microsoft phrasing, is the physical terminal of the system, which is where the system terminal, i.e. the thing I’ve described above, actually runs in so that we can type and interface with it as humans.

Albeit, as English does, these definitions aren’t always taken as the exact, appropriate, and pedantically correct definitions today. For example, many at Microsoft argue that the console is just the terminal, that the terminal is the console. Sure, ok, that’s fine I can still follow along in the conversation, and this adds context, for when someone steps out of line and uses the more historically specific definition in context of a conversation.

Alright, that’s all groovy, so now we can get back to just talking about the shell, all the power it gives the Unix/Linux/POSIX System user, and touch on the terminal or console as we need to with full context of what these things actually are!

Gnu-bash-logo.svgIntroducing Bash!

Alright, with that little bit of context around Bourne Shell, let’s talk about what we’ve actually got today running as our shell in our terminal on our console on the computers we work with! The Bourne Shell, years later had a replacement written for it by Brian Fox. He released it in 1989 and over the years it became a kind of defacto replacement of Bourne Shell. The term ‘BASH’ stands for Bourne Again SHell.

440px-Bash_screenshotThe Bash command syntax is a superset of the Bourne Shell syntax. It provides a wide range of commands that includes ideas drawn from the Korn shell (ksh) and the C shell (csh) such as command line editing, command history, the directory stack, the $RANDOM and $PPID variables, and POSIX command substitution syntax. If many of those things make you think, “WTF are these variables and such?” have no worries, I’ll get to em’ soon enough in this series!

But with that, this is the beginning of many short entries on tips, tricks, tutorials, syntax, history, and context of bash so until next time, cheers!

References & Collected Materials

Bash, Ruby, and Such Console Installation Version Management Bits for OS-X

I went to reinstall RVM (Ruby Version Manager) and got a message that the command wasn’t available. I realized, after fiddling around for a while that I didn’t have bash setup, and I had tried to run the standard quick install of:

bash < 

…I had not setup bash shell as my shell on this Mac?! Oops. So since I’m a virtual noob sometimes, and I have no idea how to setup bash, I did some searching and came up with this solution.

First, switch to bash.

chsh -s bash

Then create yourself a .bash_profile so that you’ll be able to initiate variables and such that you’ll need in the shell. These are used when working with Ruby, Rails, and a whole host of other things. To create a .bash_profile you can follow these commands.  (Snagged from this find)

cd ~/
touch .bash_profile
open -e .bash_profile

Then add this to the bash file.

# place in ~/.bash_profile as the very last line
[[ -s "$HOME/.rvm/scripts/rvm" ]] && . "$HOME/.rvm/scripts/rvm"

Now run the install (usually you’re told to setup this bash file afterwards, but figured we might as well get it done).

bash < 

Next exit (or whatever your restart of bash technique is) and open your bash terminal back up. Type this command to be sure we’re on the right path.

type rvm | head -n1

Now to install the latest Ruby on Rails bits you can issue a command like this.

rvm install 1.8.7

However, OS-X already comes with 1.8.7, so you’d probably want to install 1.9.2. I issued the 1.8.7 install since I knew, previously, I’d dorked up the install a few days ago. So it is also a good way to make sure your install is cleaned up. I’m sure though, it could possibly mess things up if you’ve tweaked things the wrong way – but it sure seems to be the case that Ruby, Rails + RVM just works. 🙂

rvm install 1.9.2

Once those are installed you’ll want to set one as default. I’m went with 1.9.2 for now. This can be changed later if need be.

rvm use 1.9.2 --default

Anyway, that’ll get you started on OS-X if you’ve run into the “I’m only running the Terminal in its default setup, I need some bash” situation. 🙂

Happy coding, hacking, and gem installing!

References:

Some references are included above as links, but these below didn’t fit exactly in context at any point, I however used them none the less.