Sorry, rough afternoon yesterday...

cat reads then writes to stdout

If you're using echo, in the sense we're discussing, it will never even see the stdin you're attempting to send. To test run the following and you'll see the test file contains the echo'd 1 

$ echo "1" > test << EOF
> 2
> EOF
$ cat test
1

Another way to see this would be:

$ > test << EOF | echo 1
> EOF
1
$ cat test
[nothing returned]

Another:

$ echo > test << EOF
> 1
> 2
> EOF
$ cat test 
[nothing returned]

You can do this:

$ echo 1 > test
$ cat test
1

It takes a while to grasp, believe me. Sometimes I'll type something out and go, "huh, why didn't that work". Then I look at it, "doh!".

read read read



On Tue, Mar 10, 2015 at 1:45 PM, Michael Havens <bmike1@gmail.com> wrote:
why would it not work with echo?

:-)~MIKE~(-:

On Tue, Mar 10, 2015 at 7:53 AM, Mike Ballon <mike.ballon@gmail.com> wrote:
First, if you're just trying to backup conf files, then simply make a backup of the conf file and restore it when needed.

To answer your question, yes, specifically with the cat command, this won't work with echo. You can test this on your own and t

$ cat > test << EOF
> 1
> 2
> 3
> EOF
$ cat test 
1
2
3
$ cat >> test << EOF
> 4
> EOF
$ cat test 
1
2
3
4

You can also start with an append if you wish:

$ cat >> test << EOF
> 1
> 2
> EOF
$ cat test 
1
2



On Mon, Mar 9, 2015 at 11:51 PM, Michael Havens <bmike1@gmail.com> wrote:
do you think this would have the desired effect?


sudo cat >> /etc/apt/apt.conf  << eof
Acquire::Queue-Mode "host";
eof

sudo cat >> /etc/sysctl.conf << eof
# 
# Reduce the swap tendency 
vm.swappiness = 10
eof

sudo cat >> /etc/apache2/apache2.conf << eof
Include /etc/phpmyadmin/apache.conf
eof

sudo cat >> /etc/fstab << eof
/media/bmike1/entertainment/Pictures /home/bmike1/Pictures none bind 0 0 
eof

would the single line appendages just need the blank line?

:-)~MIKE~(-:

On Mon, Mar 9, 2015 at 8:41 PM, Michael Havens <bmike1@gmail.com> wrote:
Okay now, I learned just today how >> works and I want to update all of my reinstall scripts so all I need to do is copy-n-paste into a terminal and everything will be done. Learned when I was doing Linux from scratch  that to create a file of multiple lines without starting an editor you do:

cat > filename << "EOF"
contents 
of
file
EOF
 Oh.... I think I get it. just turn the '>' into '>>'
am I correct? 

:-)~MIKE~(-:


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