I'd also like to mention another useful application of .inputrc.
It's the ability to attribute a command to a key press: Command Binding.
The typical case is a frequent command and an unused function key.
Lets say, just for example, prtstat -J and the F5 key.
Initially, F5 is unbound.
Wednesday, August 13, 2014
Some .inputrc detail
I've passed by the .inputrc file sometimes in the past.
It's the file associated with the readline(3), stty(1) and termio(7I).
What I'd like to do now is to show how to use all of this to present one basic (suboptimal) setting to the behavior of the Del key, specially under the sun-color terminal. The case for the xterm terminal is easier to solve by tweaking .inputrc only.
The first command to note about is bind which is a bash built-in command.
It can set and display many bash key bindings and variables.
(not to mention commands bindings)
For all options:
$ help bind
...
$ bind -P |grep -v 'not bound' |less
...
Here's an example from a tweak for a xterm terminal:
$ bind -q delete-char
delete-char can be invoked via "\C-d", "\e[3~".
Here's another example for a default sun-color terminal:
$ bind -q backward-delete-char
backward-delete-char can be invoked via "\C-h", "\C-?".
$ bind -q delete-char
delete-char can be invoked via "\C-d".
The above settings for sun-color could lead to a hard time until you figure out what's going on! This behavior of the Del key on a sun-color terminal is unacceptable! All that follows is related to the sun-color terminal type.
I was getting the following reading of the Del key:
$ read -n 1
^?
And the following reading for the Backspace key:
$ read -n 1
^H
And as seen above both "^?" and "^H" were set to backward-delete-char.
That's a nice way to drive you mad until you find out what to blame!
These default configurations may lock you in a tricky confusion.
NOTE
SUB-OPTIMAL FIX:
To help our way out of this mess, here comes the stty shell command.
But if not used with care it may actually complicate matters even more.
This is because as per termio(7I) a DEL is supposed to be Backspace!
At the same time stty says that <BS> is "^H" and <DEL>
For all stty options:
$ stty -h
The obscure solution is to tweak the terminal (tty) erase configuration.
This way, first, we restore the usual erase (Backspace) control sequence to "^h":
# stty erase '^h'
Or better yet, set it in the .bashrc:
...
if [[ "$TERM" = sun-color ]]; then
stty erase '^h'
fi
...
# stty -a
...
... erase = ^h; ...
...
Then we fix the Del key behavior by an appropriate entry in .inputrc:
...
$if term=sun-color
...
"\C-?":delete-char # Del
...
$endif
...
It's the file associated with the readline(3), stty(1) and termio(7I).
What I'd like to do now is to show how to use all of this to present one basic (suboptimal) setting to the behavior of the Del key, specially under the sun-color terminal. The case for the xterm terminal is easier to solve by tweaking .inputrc only.
The first command to note about is bind which is a bash built-in command.
It can set and display many bash key bindings and variables.
(not to mention commands bindings)
For all options:
$ help bind
...
$ bind -P |grep -v 'not bound' |less
...
Here's an example from a tweak for a xterm terminal:
$ bind -q delete-char
delete-char can be invoked via "\C-d", "\e[3~".
Here's another example for a default sun-color terminal:
$ bind -q backward-delete-char
backward-delete-char can be invoked via "\C-h", "\C-?".
$ bind -q delete-char
delete-char can be invoked via "\C-d".
The above settings for sun-color could lead to a hard time until you figure out what's going on! This behavior of the Del key on a sun-color terminal is unacceptable! All that follows is related to the sun-color terminal type.
I was getting the following reading of the Del key:
$ read -n 1
^?
And the following reading for the Backspace key:
$ read -n 1
^H
And as seen above both "^?" and "^H" were set to backward-delete-char.
That's a nice way to drive you mad until you find out what to blame!
These default configurations may lock you in a tricky confusion.
NOTE
Some years later while investigating how to better adjust the layout of my keyboard while at the console, I've found out more about this issue around "^?" and "^H". In fact, I would have to dig more into terminal operations, but it may help to add that by default the backspace key must generate what terminal expect which is "^?" and not "^H". In fact, the best way to adjust this is not as I'll show below, but by reconfiguring the keyboard as shown on this other more recent post: Keyboard - Layouts.
SUB-OPTIMAL FIX:
To help our way out of this mess, here comes the stty shell command.
But if not used with care it may actually complicate matters even more.
This is because as per termio(7I) a DEL is supposed to be Backspace!
At the same time stty says that <BS> is "^H" and <DEL>
For all stty options:
$ stty -h
The obscure solution is to tweak the terminal (tty) erase configuration.
This way, first, we restore the usual erase (Backspace) control sequence to "^h":
# stty erase '^h'
Or better yet, set it in the .bashrc:
...
if [[ "$TERM" = sun-color ]]; then
stty erase '^h'
fi
...
# stty -a
...
... erase = ^h; ...
...
Then we fix the Del key behavior by an appropriate entry in .inputrc:
...
$if term=sun-color
...
"\C-?":delete-char # Del
...
$endif
...
Monday, August 4, 2014
Solaris 11.2 (General Availability)
Last Friday was a great day!
Solaris 11.2 General Availability (GA) was made available!
The main propaganda is around the integration with Open Stack.
That's a way to leverage the underlying Solaris technologies.
So far I haven't tried OpenStack but perhaps someday.
This is an interesting milestone:
I had to download around 8 GB of essential installers and repositories.
I'm expecting to meet newer versions of many pre-packaged software.
We'll see.
Solaris 11.2 General Availability (GA) was made available!
The main propaganda is around the integration with Open Stack.
That's a way to leverage the underlying Solaris technologies.
So far I haven't tried OpenStack but perhaps someday.
This is an interesting milestone:
Oracle was originally investing on its proprietary software.I hope this new release continues to be a solid step onwards.
I mean the Enterprise Manager Ops Center solution and add-ins.
Perhaps I should be glad I have invested almost no precious time on it.
According to my experience and first impressions I decided to wait.
But of course I have kept an eye on it as one never knows.
With Open Stack Oracle may have performed a clever step.
But of course things will depend on the Open Source community.
We'll see.
I had to download around 8 GB of essential installers and repositories.
I'm expecting to meet newer versions of many pre-packaged software.
We'll see.
Friday, August 1, 2014
DNS configuration file
By default, the DNS configuration file is /etc/named.conf.
The location of this file is good and bad at the same time.
It's good because it's on a standard UNIX location.
It's bad because it isn't on dedicated directory.
In order to improve administration it's necessary to dedicate a more stable directory and decouple, as much as possible, configuration detail that are subject to more frequent changes (DNS zone data) from those that don't, such as global options.
Consider all the assumptions presented in my DNS configuration.
There are two scenarios, one of them specific to a DNS internal root.
I) The DNS internal root main configuration file could be:
(This is for internal root servers A, B, C and D)
#
# Business Corp.
#
# DNS internal root main configuration file.
# Global options should be gathered on this file.
# last update: August 1, 2014.
#
options {
version none;
directory "/var/named";
# ...
};
# Internal root.
zone "." in {
type master;
file "db.root";
recursion no;
};
# Loopback zone.
zone "0.0.127.in-addr.arpa." in {
type master;
file "db.127.0.0";
notify no;
};
# End of File.
II) The internal DNS server main configuration file could be:
(This is for internal top-level servers NS00, NS01 and NS02)
#
# Business Corp.
#
# DNS internal server main configuration file.
# Global options should be gathered on this file.
# last update: August 1, 2014.
#
options {
version none;
directory "/var/named";
# ...
};
# Internal root.
zone "." in {
type hint;
file "db.cache";
recursion no;
};
# Loopback zone.
zone "0.0.127.in-addr.arpa." in {
type master;
file "db.127.0.0";
notify no;
};
# Zones data (more frequently changed)
include "named.zones";
# End of File.
As soon as I'm satisfied with the global options the file won't change.
This is precisely my intention: administration limited to /var/named.
The file /var/named/named.zones will have other nested includes.
Most probably or ideally one additional nesting (include file) per zone.
The location of this file is good and bad at the same time.
It's good because it's on a standard UNIX location.
It's bad because it isn't on dedicated directory.
In order to improve administration it's necessary to dedicate a more stable directory and decouple, as much as possible, configuration detail that are subject to more frequent changes (DNS zone data) from those that don't, such as global options.
Consider all the assumptions presented in my DNS configuration.
There are two scenarios, one of them specific to a DNS internal root.
I) The DNS internal root main configuration file could be:
(This is for internal root servers A, B, C and D)
#
# Business Corp.
#
# DNS internal root main configuration file.
# Global options should be gathered on this file.
# last update: August 1, 2014.
#
options {
version none;
directory "/var/named";
# ...
};
# Internal root.
zone "." in {
type master;
file "db.root";
recursion no;
};
# Loopback zone.
zone "0.0.127.in-addr.arpa." in {
type master;
file "db.127.0.0";
notify no;
};
# End of File.
II) The internal DNS server main configuration file could be:
(This is for internal top-level servers NS00, NS01 and NS02)
#
# Business Corp.
#
# DNS internal server main configuration file.
# Global options should be gathered on this file.
# last update: August 1, 2014.
#
options {
version none;
directory "/var/named";
# ...
};
# Internal root.
zone "." in {
type hint;
file "db.cache";
recursion no;
};
# Loopback zone.
zone "0.0.127.in-addr.arpa." in {
type master;
file "db.127.0.0";
notify no;
};
# Zones data (more frequently changed)
include "named.zones";
# End of File.
As soon as I'm satisfied with the global options the file won't change.
This is precisely my intention: administration limited to /var/named.
The file /var/named/named.zones will have other nested includes.
Most probably or ideally one additional nesting (include file) per zone.
DNS zone data source files
There is a tedious aspect of setting up DNS zone data.
It how it will or should be organized within the file system.
This particular post seeks to address this specific point.
I'll take the same approach used for NIS maps' source files.
Please, visit that other post for a longer description and consideration.
# zfs create rpool/VARSHARE/named
# zfs list -t all -r rpool/VARSHARE
NAME USED AVAIL REFER MOUNTPOINT
rpool/VARSHARE 52K 11.8G 40K /var/share
rpool/VARSHARE/named 31K 11.8G 31K /var/share/named
# chmod -R 750 /var/share/named
# ln -s /var/shared/named /var/named
# ls -lh /var | grep ^l
...
lrwxrwxrwx 1 root root ... dns -> /var/share/named
...
For further organization no additional ZFS file systems are needed.
A simple directory structure within /var/named will do.
Configure the directory option accordingly in /etc/named.conf:
options {
# ...
directory "/var/named";
# ...
};
It how it will or should be organized within the file system.
This particular post seeks to address this specific point.
I'll take the same approach used for NIS maps' source files.
Please, visit that other post for a longer description and consideration.
# zfs create rpool/VARSHARE/named
# zfs list -t all -r rpool/VARSHARE
NAME USED AVAIL REFER MOUNTPOINT
rpool/VARSHARE 52K 11.8G 40K /var/share
rpool/VARSHARE/named 31K 11.8G 31K /var/share/named
# chmod -R 750 /var/share/named
# ln -s /var/shared/named /var/named
# ls -lh /var | grep ^l
...
lrwxrwxrwx 1 root root ... dns -> /var/share/named
...
For further organization no additional ZFS file systems are needed.
A simple directory structure within /var/named will do.
Configure the directory option accordingly in /etc/named.conf:
options {
# ...
directory "/var/named";
# ...
};
DNS zone data
Apart from installing and configuring DNS itself, a crucial preliminary step is to structure and prepare the DNS zone data source files. In what follows, I assume that all the structure and contents have been addressed as defined on the preceding posts (previous links).
Take the internal DNS servers NS00 thru NS02 (below DNS internal roots).
Their named.zones included by /etc/named.conf could be as follows:
zone "business.corp" {
type master;
file "master/db.business.corp";
};
zone "10.in-addr.arpa" {
type master;
file "master/db.10";
};
zone "168.192.in-addr.arpa" {
type master;
file "master/db.192.168";
};
NOTE
I) business.corp
;
; Business Corp.
;
; Internal DNS (top-level) server forward zone.
; last update: August 5, 2014.
;
$TTL 3h
@ IN SOA NS00.business.corp. hostmaster.business.corp. (
1 ; Serial
3h ; Refresh after 3 hours
1h ; Retry after 1 hour
1w ; Expire after 1 week
1h ) ; Negative caching TTL of 1 hour
; Authoritative name servers.
IN NS NS00.business.corp.
IN NS NS01.business.corp.
IN NS NS02.business.corp.
; The internal root servers A records.
A IN A 10.0.0.10
B IN A 10.0.0.20
C IN A 10.0.0.30
D IN A 10.0.0.40
; The internal top-level servers A records.
NS00 IN A 10.0.1.10
NS01 IN A 10.0.1.20
NS02 IN A 10.0.1.30
; Other internal hosts A records.
; ...
; End of File.
II) 10.in-addr.arpa
;
; Business Corp.
;
; Internal DNS (top-level) server reverse zone.
; last update: August 5, 2014.
;
$TTL 3h
@ IN SOA NS00.business.corp. hostmaster.business.corp. (
1 ; Serial
3h ; Refresh after 3 hours
1h ; Retry after 1 hour
1w ; Expire after 1 week
1h ) ; Negative caching TTL of 1 hour
; Authoritative name servers.
IN NS NS00.business.corp.
IN NS NS01.business.corp.
IN NS NS02.business.corp.
; The internal root servers PTR records.
10.0.0 IN PTR A.business.corp.
20.0.0 IN PTR B.business.corp.
30.0.0 IN PTR C.business.corp.
40.0.0 IN PTR D.business.corp.
; The internal top-level servers PTR records.
10.1.0 IN PTR NS00.business.corp.
20.1.0 IN PTR NS01.business.corp.
30.1.0 IN PTR NS02.business.corp.
; Other internal hosts PTR records.
; ...
; End of File.
III) 168.192.in-addr.arpa
;
; Business Corp.
;
; Internal DNS (top-level) server reverse zone.
; last update: August 5, 2014.
;
$TTL 3h
@ IN SOA NS00.business.corp. hostmaster.business.corp. (
1 ; Serial
3h ; Refresh after 3 hours
1h ; Retry after 1 hour
1w ; Expire after 1 week
1h ) ; Negative caching TTL of 1 hour
; Authoritative name servers.
IN NS NS00.business.corp.
IN NS NS01.business.corp.
IN NS NS02.business.corp.
; Other internal hosts PTR records.
; ...
; End of File.
Take the internal DNS servers NS00 thru NS02 (below DNS internal roots).
Their named.zones included by /etc/named.conf could be as follows:
zone "business.corp" {
type master;
file "master/db.business.corp";
};
zone "10.in-addr.arpa" {
type master;
file "master/db.10";
};
zone "168.192.in-addr.arpa" {
type master;
file "master/db.192.168";
};
NOTE
Of course, it's not recommended to have a multi-master setup.The contents of each of the above zone data file in master is as follows:
This means, just as example, that only NS00 should be master.
Hence, it suffices to substitute master for slave for NS01 and NS02.
I) business.corp
;
; Business Corp.
;
; Internal DNS (top-level) server forward zone.
; last update: August 5, 2014.
;
$TTL 3h
@ IN SOA NS00.business.corp. hostmaster.business.corp. (
1 ; Serial
3h ; Refresh after 3 hours
1h ; Retry after 1 hour
1w ; Expire after 1 week
1h ) ; Negative caching TTL of 1 hour
; Authoritative name servers.
IN NS NS00.business.corp.
IN NS NS01.business.corp.
IN NS NS02.business.corp.
; The internal root servers A records.
A IN A 10.0.0.10
B IN A 10.0.0.20
C IN A 10.0.0.30
D IN A 10.0.0.40
; The internal top-level servers A records.
NS00 IN A 10.0.1.10
NS01 IN A 10.0.1.20
NS02 IN A 10.0.1.30
; Other internal hosts A records.
; ...
; End of File.
II) 10.in-addr.arpa
;
; Business Corp.
;
; Internal DNS (top-level) server reverse zone.
; last update: August 5, 2014.
;
$TTL 3h
@ IN SOA NS00.business.corp. hostmaster.business.corp. (
1 ; Serial
3h ; Refresh after 3 hours
1h ; Retry after 1 hour
1w ; Expire after 1 week
1h ) ; Negative caching TTL of 1 hour
; Authoritative name servers.
IN NS NS00.business.corp.
IN NS NS01.business.corp.
IN NS NS02.business.corp.
; The internal root servers PTR records.
10.0.0 IN PTR A.business.corp.
20.0.0 IN PTR B.business.corp.
30.0.0 IN PTR C.business.corp.
40.0.0 IN PTR D.business.corp.
; The internal top-level servers PTR records.
10.1.0 IN PTR NS00.business.corp.
20.1.0 IN PTR NS01.business.corp.
30.1.0 IN PTR NS02.business.corp.
; Other internal hosts PTR records.
; ...
; End of File.
III) 168.192.in-addr.arpa
;
; Business Corp.
;
; Internal DNS (top-level) server reverse zone.
; last update: August 5, 2014.
;
$TTL 3h
@ IN SOA NS00.business.corp. hostmaster.business.corp. (
1 ; Serial
3h ; Refresh after 3 hours
1h ; Retry after 1 hour
1w ; Expire after 1 week
1h ) ; Negative caching TTL of 1 hour
; Authoritative name servers.
IN NS NS00.business.corp.
IN NS NS01.business.corp.
IN NS NS02.business.corp.
; Other internal hosts PTR records.
; ...
; End of File.
Subscribe to:
Posts (Atom)