There are also some newer editors that use LUA as the scripting language, but none with Perl as a scripting language. See https://www.slant.co/topics/7340/~open-source-programmable-text-editors

Here, for example, is a fragment from an old collection of hardening scripts called Titan, written for Solaris by Brad M. Powell. Example below uses vi which is the simplest, but probably not optimal choice, unless your primary editor is VIM.

FixHostsEquiv() {

if  [ -f /etc/hosts.equiv -a -s /etc/hosts.equiv ]; then
      t_echo 2 " /etc/hosts.equiv exists and is not empty. Saving a co
+py..."
      /bin/cp /etc/hosts.equiv /etc/hosts.equiv.ORIG

        if grep -s "^+$" /etc/hosts.equiv
        then
        ed - /etc/hosts.equiv <<- !
        g/^+$/d
        w
        q
        !
        fi
else
        t_echo 2 "        No /etc/hosts.equiv -  PASSES CHECK"
        exit 1
fi
[download]

For VIM/Emacs users the main benefit here is that you will know your editor better, instead of inventing/learning "yet another tool." That actually also is an argument against Ansible and friends: unless you operate a cluster or other sizable set of servers, why try to kill a bird with a cannon. Positive return on investment probably starts if you manage over 8 or even 16 boxes.

Perl also can be used. But I would recommend to slurp the file into an array and operate with lines like in editor; a regex on the whole text are more difficult to write correctly then a regex for a line, although experts have no difficulties using just them. But we seldom acquire skills we can so without :-)

On the other hand, that gives you a chance to learn splice function ;-)

If the files are basically identical and need some slight customization you can use patch utility with pdsh, but you need to learn the ropes. Like Perl the patch utility was also written by Larry Wall and is a very flexible tool for such tasks. You need first to collect files from your servers into some central directory with pdsh/pdcp (which I think is a standard RPM on RHEL and other linuxes) or other tool, then to create diffs with one server to which you already applied the change (diff is your command language at this point), verify that on other server that this diff produced right results, apply it and then distribute the resulting files back to each server using again pdsh/pdcp. If you have a common NFS/GPFS/LUSTRA filesystem for all servers this is even simpler as you can store both the tree and diffs on common filesystem.

The same central repository of config files can be used with vi and other approaches creating "poor man Ansible" for you .

2020-10-05&06 Athanasius changed <pre> to <code> tags, &quot; to ", etc.