[CentOS] Postfix setup

Tue Mar 12 14:02:13 UTC 2013
James B. Byrne <byrnejb at harte-lyne.ca>

On Mon, March 11, 2013 16:56, Craig White wrote:

>
> ----
> develop good, consistent habits
 postfix or whatever config files you
> edit, backup the distribution's version of the config file first
> before you ever edit

>
> cp main.cf main.cf-dist
>

Alternatively:

yum install postfix
yum install git
cd /etc/posfix
git init
git add ./
git commit -m"Postfix config file initial commit"

Now all the default config files are stored as hashed blobs in
/etc/postfix/.git and you can modify them in place.  Once you are
satisfied with your latest set of changes do this (always issue git
commands from the repository root, in this case /etc/postfix):

git add ./  or  git add <filename>
git commit -m"explanation of why the changes were made"

If you screw up and need to get back what was there originally do this:

git checkout <filename>

If you want to see what was different between this config and the
previous version do this:

git diff <filename>

You can compare any previous version of any tracked file with any
other version of the same file by specifying the commit ids.

git diff <commit1_sha>..<commit2_sha> -- <filename>

Git also provides a blow by blow history of all changes applied to a
file and what logon id made them.

git blame <commit1_sha>..<commit2_sha> -- <filename>

See http://git-scm.com/ for details on what git is and how to use it. 
I use git for version control of system config files on all my uptime
sensitive servers.  It makes getting back to a working config trivial
when things turn ugly following a change.

-- 
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James B. Byrne                mailto:ByrneJB at Harte-Lyne.ca
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