These are the full instructions for installing libmad. I'm trying to figure out what the part with "cat" does. From what I know about "here docs," "here docs" are supposed to be embedded in scripts. Below, I understand how the input following the file /usr/lib/pkgconfig/mad.pc is concatenated with the file. However, I don't understand how the "here doc" format works with using "cat" from the command line. I can't tell if these instructions are telling me to add from "cat" to "EOF" to some script or if I am supposed to use it just like a "cat" command.


Installation of libmad

Install libmad by running the following commands:

./configure --prefix=/usr &&
make

This package does not come with a test suite.

Now, as the root user:

make install

Some packages check for the pkg-config file for libmad. This file is particularly needed so that Cdrdao can recognize the installed libmad.

As the root user:

cat > /usr/lib/pkgconfig/mad.pc << "EOF"
prefix=/usr
exec_prefix=${prefix}
libdir=${exec_prefix}/lib
includedir=${prefix}/include

Name: mad
Description: MPEG audio decoder
Requires:
Version: 0.15.1b
Libs: -L${libdir} -lmad
Cflags: -I${includedir}
EOF

This is a regular cat command with input (the green part) and redirected output (the blue part). The here-document (all between "EOF" and EOF) is a container that holds the input. All this is one command.

You can copy/paste (or type) this in the shell. You will see a > (the PS2 prompt) at the beginning of the lines when you type or copy/paste, this is bash telling you that it hasn't seen the closing EOF (command isn't complete yet).

Hope this helps.

So, just so I can be clear, the << simply tells cat that everything between the EOFs will be concatenated with /usr/lib/pkgconfig/mad.pc.

Also, I appreciate your reponse.

Everything in the heredoc is sent to the stdin of cat, and the stdout of cat is redirected into the filename.

Redirections, including heredocs, need to be associated with a process. In this case cat simply acts as a "pipe" between the heredoc and the file.

Thank you David and Druuna.

You're welcome

BTW: Can you put up the [SOLVED] tag.
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