explanation about EOF pls... 3

[adaaje]

Hi guys,

I've got the code...

#!/bin/sh
echo 'what is the value? '
read value
cat <<EOF
The value is $value
EOF

what's the EOF means pls? and what does it do?

 

[Salem]

In this context, EOF can be any word.

They're called 'here' documents.

http://www.tldp.org/LDP/abs/html/here-docs.html

In short, it's an easy way of including short bits of text inside the shell script without having to do excessive amounts of quoting, and without having to create a separate file.

--

 

[adaaje]

Thanks Salem,

#!/bin/sh
echo -n 'what is the value? '
read value
sed  's/XXX/'$value'/' <<EOF
The value is XXX
EOF

what about this ?? what the XXX means pls?

 

[Annihilannic]

Are you sure this isn't homework??

Did you read and understand the link Salem posted?

XXX is nothing special, it's just a piece of text. The sed script is used to replace it with something else, in this case the contents of the value variable.

Annihilannic.

 

[feherke]

Hi

The content of the here-document is passed as input to the command on left side of the less-then signs ( < ).

So in the first code the [tt]cat[/tt] command get the text and output it. In the second code the [tt]sed[/tt] command get the text, execute the [tt]s///[/tt] command on the text, then output it.

If this was the missing chain.

Feherke.

http://rootshell.be/~feherke/

 

[adaaje]

Hi Annihilannic,

Thanks for being "nice", but I know that
sed 's/XXX/$value'

sed 's/[old pattern]/[new pattern]/'
is normally replacing XXX with $value,
but in this case $value replacing XXX

why?? that's the question ???

 

[adaaje]

I got it,

thanks

 

[Annihilannic]

!??!?!! I'm sorry, I don't understand which part you don't understand.

"replacing XXX with $value" and "$value replacing XXX" means exactly the same thing?

Annihilannic.

 

[Annihilannic]

Oh, good.

Annihilannic.