EggXpert

Hey everyone.. I am taking a linux class at school and being a windows user makes it hard to understand certain concepts.. I have a couple questions hopefully someone can make them easy for me to understand... We are talking about commands and using the echo command... what does this exactly do, I know it like prints what you write to the screen or terminal but i don't really undestand... for example one command we talk about is echo $USER of $HOME... can some try to explain the whole echo concept... another question is what is the significance of the $, if there is any.. lastly does anyone have any good books or websites for beginners to help understand the terminal and commands... thanks soo much

http://lowfatlinux.com/linux-echo-command.html

This explains a lot about it :

 

 

The echo command displays a message on the screen and is primarily useful for programmers writing shell scripts (see "Linux Programming"). But anyone can use echo to show the value of environment variables. The echo command displays a message on the screen and is primarily useful for programmers writing shell scripts (see "Linux Programming"). But anyone can use echo to show the value of environment variables. Here are some examples:

echo $PATH
/usr/bin:/usr/local/bin
echo My name is $USER - Home directory=$HOME.
My name is hermie - Home directory=/home/hermie.

The echo command is very similar to the DOS command of the same name, except that the DOS echo command cannot display environment variables--it just displays a message.

echo is a program used to show text. It can echo back what you type, or it can echo things such as environment variables ($HOME, $USER is an environment variable). Echo can also be used to pipe text to another program. For example:

echo hello world | wall  

the | symbol is a pipe. In the most basic sense it is like saying "take the text hello world and send it to wall"

$HOME, $USER is a variable. It contains information. In order to access the contents of the variable you have to use the $ symbol. 

If you wanted to, you can say just $HOME and then press enter, but you will be given an error, and that's not a very good idea either. Because without echo what you type on the shell will be interpreted as a command, or other things.... which I won't get into because I'll just confuse you even more.

So when you want to show text, you can use echo. If you want to send text to a file. You say echo "hello world" > my_file_name 

Again, without using echo here, "hello world" will be interpreted as a command.  The > symbol is used to redirect the text of "hello world" to a file.

You should also type 'man echo' without the quotes the next time you're in linux. The program 'man' will show you the manual of echo, the manuals can be a bit complicated to read, but you will get used to them. :)

A good beginners guide: 

http://www.linux.org/lessons/beginner/index.html 

good luck and have fun  

 EDIT:

Btw, you can type the command 'env' to show all of your environment variables. That is where $HOME and $USER is.

You should get a Live linux cd such as knoppix, you don't need to install it to your HD. It will run from your DVD/CD drive. The best way to learn linux is to use it, use it often, and read the man pages to find out what stuff does. 

dhthwy:

echo is a program used to show text. It can echo back what you type, or it can echo things such as environment variables ($HOME, $USER is an environment variable). Echo can also be used to pipe text to another program. For example:

echo hello world | wall  

the | symbol is a pipe. In the most basic sense it is like saying "take the text hello world and send it to wall"

$HOME, $USER is a variable. It contains information. In order to access the contents of the variable you have to use the $ symbol. 

If you wanted to, you can say just $HOME and then press enter, but you will be given an error, and that's not a very good idea either. Because without echo what you type on the shell will be interpreted as a command, or other things.... which I won't get into because I'll just confuse you even more.

So when you want to show text, you can use echo. If you want to send text to a file. You say echo "hello world" > my_file_name 

Again, without using echo here, "hello world" will be interpreted as a command.  The > symbol is used to redirect the text of "hello world" to a file.

You should also type 'man echo' without the quotes the next time you're in linux. The program 'man' will show you the manual of echo, the manuals can be a bit complicated to read, but you will get used to them. :)

A good beginners guide: 

http://www.linux.org/lessons/beginner/index.html 

good luck and have fun  

 EDIT:

Btw, you can type the command 'env' to show all of your environment variables. That is where $HOME and $USER is.

You should get a Live linux cd such as knoppix, you don't need to install it to your HD. It will run from your DVD/CD drive. The best way to learn linux is to use it, use it often, and read the man pages to find out what stuff does. 

If I could rate this post I'd give you 5 eggs

 

lol thanks. I've been postin alot today to get me outta the embryo tier and thus far nobody has given me any eggs :<

Heh. One day they will bring back the ranking system.

 

Hey root, i can still see the eggs and rank the posts.  You just have to wait for them

Or did they kill the system thus rendering my rating useless? 

kunzy:

Or did they kill the system thus rendering my rating useless?