Ubuntu¶
ssh¶
In order to prevent the SSH RSA key verification, you can use the following option with ssh. -o StrictHostKeyChecking=no
phoe6: In xterm, I can change the size of fonts and windows by doing Control + Right Click and Selecting Huge from the VT Font menu. Can I have this setting in the .Xresources file? I am not able to find out what I should do.
phoe6: Everytime I don’t want to do a CTRL+RIGHT CLICK + Select Huge VT Font. I want it as my standard configuration.
place the following in .Xresources or .Xdefault
- ::
- Xterm.*font: 10x20 .Xresources is a one time load event when you starup the window manager. .Xdefaults is loaded on every xterm window.
For more info man X or man xterm
For list of fonts,xlsfonts Edit .Xdefaults in your home directory and add a line as follows:
font: 9x15
font: -adobe-courier-medium-r-normal-*-14-*-*-*-*-*-*-*
The next time you start an X session, you should have the specified font as your default.
You want a line like:
XTerm*VT100*font: Fixed
(except different). Look in your app-defaults/XTerm file for clues.
My Constant thoughts with Ubuntu is to how to automate various tasks that I routinely do.
ratpoison window manager related: * starting nm-applet automatically. mutt folders. office email via mutt.
fetchmail automatically. http://ubuntuforums.org/showthread.php?t=175438
Ubuntu Bash Shortcuts¶
Ctrl-a Move to the start of the line. Ctrl-e Move to the end of the line. Alt-] x Moves the cursor forward to the next occurrence of x. Alt-Ctrl-] x Moves the cursor backwards to the previous occurrence of x. Ctrl-u Delete from the cursor to the beginning of the line. Ctrl-k Delete from the cursor to the end of the line. Ctrl-w Delete from the cursor to the start of the word. Ctrl-y Pastes text from the clipboard. Ctrl-l Clear the screen leaving the current line at the top of the screen. Ctrl-x Ctrl-u Undo the last changes. Ctrl-_ Alt-r Undo all changes to the line. Alt-Ctrl-e Expand command line. Ctrl-r Incremental reverse search of history. Alt-p Non-incremental reverse search of history. !! Execute last command in history !abc Execute last command in history beginning with abc !n Execute nth command in history ^abc^xyz Replace first occurrence of abc with xyz in last command and execute it
httpd¶
Also at this point, you can specify which features you want included in Apache HTTPd by enabling and disabling modules. The Apache HTTP Server comes with a Base set of modules included by default. Other modules are enabled using the –enable-module option, where module is the name of the module with the mod_string removed and with any underscore converted to a dash. You can also choose to compile modules as shared objects (DSOs) – which can be loaded or unloaded at runtime – by using the option –enable-module=shared. Similarly, you can disable Base modules with the –disable-module option. Be careful when using these options, since configure cannot warn you if the module you specify does not exist; it will simply ignore the option.
Ubuntu’s HTTPD Document gives a general overview. https://help.ubuntu.com/8.04/serverguide/C/httpd.html
To enable the mod_filter and mod_ext_filter I had to do: sudo a2enmod ext_filter sudo a2enmod filter
[08:59:48 senthil]$sudo a2enmod ext_filter
Enabling module ext_filter.
Run '/etc/init.d/apache2 restart' to activate new configuration!
[/etc/apache2/mods-available]
[09:00:14 senthil]$sudo a2enmod filter
Enabling module filter.
Run '/etc/init.d/apache2 restart' to activate new configuration!
The text replacement at the response worked properly.
# mod_ext_filter directive to define a filter which
# replaces text in the response
#
ExtFilterDefine fixtext mode=output intype=text/html \
cmd="/bin/sed s/verdana/arial/g"
<Location />
# core directive to cause the fixtext filter to
# be run on output
SetOutputFilter fixtext
</Location>
Now I can slow down the server too..
mutt¶
#======================================================#
# Boring details
set realname = "Senthil Kumaran"
set from = "orsenthil@gmail.com"
set use_from = yes
set envelope_from ="yes"
# If not set in environment variables:
set spoolfile = /var/spool/mail/ors
#======================================================#
# Folders
set folder="~/Mail" # Mailboxes in here
set record="+sent" # where to store sent messages
set postponed="+postponed" # where to store draft messages
set move=yes # Don't move mail from the spool.
#======================================================#
# Watch these mailboxes for new mail:
mailboxes ! +Fetchmail +slrn +mutt
set sort_browser=alpha # Sort mailboxes by alpha(bet)
#======================================================#
# Order of headers and what to show
hdr_order Date: From: User-Agent: X-Mailer \
To: Cc: Reply-To: Subject:
ignore *
unignore Date: From: User-Agent: X-Mailer \
To: Cc: Reply-To: Subject:
#======================================================#
# which editor do you want to use?
# vim of course!
set editor="vim -c 'set tw=70 et' '+/^$' "
set edit_headers # See the headers when editing
#======================================================#
# Aliases
set sort_alias=alias # sort aliases in alpha order by alias name
#======================================================#
# Sorting
set sort=threads
set sort_aux=subject
#======================================================#
# Colours: This scheme is fairly basic and only
# really works if your Terminal background is white
#color hdrdefault black default
#color quoted red default
#color signature brightblack default
#color indicator brightwhite red
#color attachment black green
#color error red default
#color message blue default
#color search brightwhite magenta
#color status brightyellow blue
#color tree red default
#color normal blue default
#color tilde green default
#color bold brightyellow default
#color markers red default
#======================================================#
# Experiments with Suitable Colors
#
color hdrdefault green default
color header yellow default Subject*
color header yellow default From*
color quoted blue default
color signature green default
color indicator yellow default
color attachment white default
color error red cyan
color message magenta cyan
color search white default
color status red cyan
color tree magenta default
color normal cyan default
color tilde green default
color bold brightyellow default
color markers red default
#======================================================#
# Odds and ends
#
set markers # mark wrapped lines of text in the pager with a +
set smart_wrap # Don't wrap mid-word
set pager_context=5 # Retain 5 lines of previous page when scrolling.
set status_on_top # Status bar on top.
set sendmail_wait=-1
#======================================================#
# To deal with HTML mails.
#
set implicit_autoview
auto_view text/html application/x-pgp-message
set mailcap_path = "~/.mailcap"
macro index \cb |urlview\n 'call urlview to extract URLs out of a message'
push <show-version> # Shows mutt version at startup
alias ssk_friends ssk_friends <SSK_friends@yahoogroups.co.in>
Makefile¶
- Makefile contains a list of rules and dependencies on how to build a program.
From: Tim Chase Subject: Re: appending and incrementing the numbers from a particular point To: Senthil Kumaran
> My requirement is to add more rows with incrementing numbers upto say 2300.
> like:
> 2191 Default SomeText
> 2192 Default SomeText.
> 2193
> 2194
> 2195
> .
> .
> .
> .
> .
> 2300
> ~
> ~
> How should I go about doing this in vim.
Well, there are several ways to go about it (as usual...this *is* vim ;)
The first that comes to mind is something like the following:
:let i=2193 | while (i <= 3000) | put =i | let i=i+1 | endwhile
When executed on the "2192" line, will add a whole bunch of other lines
afterwards. If you want your default text stuff in there too, you can
simply change the "put =i" to
put =i." Default Some Text"
which will pre-populate it with values if you want. If you like to be
left at the top of that inserted stuff, you can try the inverse. On a
blank/emtpy line below "2192", you can do
:let i=3000 | while (i > 2192) | put! =i | let i=i-1 | endwhile
This would be a direct answer to your question of "how to add more rows,
incrementing a number each time".
If, however, you'd like to have it auto-number, something like this
mapping might do the trick for you (all one line):
:inoremap <cr> <cr><c-o>:let i=substitute(getline(line('.')-1),
'^\(\d*\).*', '\1', '')<cr><c-r>=i>0?(i+1).' ':''<cr>
It can be done without a holding "i" variable, but it becomes about
twice as large, as both instances of "i" would be replaced with the
entire contents of the "substitute()" call.
It should gracefully handle lines with numbers and lines without numbers.
Help on the following topics should give you more details on what's
going on there.
:help getline()
:he line()
:he i_^R
:he while
:he let
:he :put
:he substitute()
:he /\d
Hope this helps,
When executed on the "2192" line, will add a whole bunch of other lines
afterwards. If you want your default text stuff in there too, you can
simply change the "put =i" to
put =i." Default Some Text"
If someone is relying on this. The change should be:
put = i . \"Default Text\"
Note the space between the . and escape of quotes.
Auto scrolling of text in vim. http://vim.wikia.com/wiki/Automatic_scrolling_of_text
! this are Xresources to make xterm look good ! put into ~/.Xresources ! after changing contents, run xrdb -merge .Xresources ! gentoo has a bug so that it doesnt read it when X starts, so add above ! command to /etc/xfce4/xinitrc (top) and be happy.
!xterm*background: Black
!xterm*foreground: Grey
xterm*font: -Misc-Fixed-Medium-R-Normal--20-200-75-75-C-100-ISO10646-1
!xterm*font: -misc-fixed-medium-r-normal--18-*-*-*-*-*-iso10646-1
!xterm*iconPixmap: ...
!xterm*iconPixmap: /usr/share/pixmaps/gnome-gemvt.xbm
!xterm*iconMask: /usr/share/pixmaps/gnome-gemvt-mask.xbm
!XTerm*iconName: terminal
!Mwm*xterm*iconImage: /home/a/a1111aa/xterm.icon
XTerm*loginShell: true
XTerm*foreground: gray90
XTerm*background: black
XTerm*cursorColor: rgb:00/80/00
XTerm*borderColor: white
XTerm*scrollColor: black
XTerm*visualBell: true
XTerm*saveLines: 1000
!! XTerm.VT100.allowSendEvents: True
XTerm*allowSendEvents: True
XTerm*sessionMgt: false
!XTerm*eightBitInput: false
!XTerm*metaSendsEscape: true
!XTerm*internalBorder: 10
!XTerm*highlightSelection: true
!XTerm*VT100*colorBDMode: on
!XTerm*VT100*colorBD: blue
!XTerm.VT100.eightBitOutput: true
!XTerm.VT100.titeInhibit: false
XTerm*color0: black
XTerm*color1: red3
XTerm*color2: green3
XTerm*color3: yellow3
XTerm*color4: DodgerBlue1
XTerm*color5: magenta3
XTerm*color6: cyan3
XTerm*color7: gray90
XTerm*color8: gray50
XTerm*color9: red
XTerm*color10: green
XTerm*color11: yellow
XTerm*color12: blue
XTerm*color13: magenta
XTerm*color14: cyan
XTerm*color15: white
XTerm*colorUL: yellow
XTerm*colorBD: white
!XTerm*mainMenu*backgroundPixmap: gradient:vertical?dimension=400&start=gray10&end=gray40
!XTerm*mainMenu*foreground: white
!XTerm*vtMenu*backgroundPixmap: gradient:vertical?dimension=550&start=gray10&end=gray40
!XTerm*vtMenu*foreground: white
!XTerm*fontMenu*backgroundPixmap: gradient:vertical?dimension=300&start=gray10&end=gray40
!XTerm*fontMenu*foreground: white
!XTerm*tekMenu*backgroundPixmap: gradient:vertical?dimension=300&start=gray10&end=gray40
!XTerm*tekMenu*foreground: white
!XTerm Profiles (idea from dag wieers)
XTerm*rightScrollBar: true
Networking¶
CIDR Notation is 192.168.0.0/16 this is equivalent to subnet mask of 255.255.0.0
When proxy server does not validate or modify any requests from the client and passes the request directly to the server, it is called gateway or tunneling proxy.
A Reverse proxy is a front end to cache and accelerate, in-demand resources. The term ‘transparent proxy’ is mostly incorrectly used to mean ‘intercepting proxy’ Because the client does not need to contact a proxy and cannot figure out if that is proxied. (for e.g at Akamai). The transparent proxies can be implemented using the Cisco’s web cache control protocol.
Reverse proxy is installed on the neighbourhood of web-server. Reverse proxy can be used for SSL Authentication; Load Balancing to the transfer the load the any of the web servers.
iptables is a userspace application that allows a system administrator to configure tables provided by Netfilter chains and rules it stores. iptables refer to the kernel level component the Xtables, that does the actual table traversal and provides an API for kernel level extensions.
iptables allow to define tables containing chains of rules. There are three default chains, INPUT, OUTPUT, FORWARD in the filter table.
iptables-save -c > iptables-configuration.txt iptables –flush iptables-restore < iptables-configuration.txt
wget works through proxy if the environment variables are http_proxy and https_proxy.
Squid¶
# Shortcuts filter=”ipttables -t filter” nat=”iptables -t nat”
# Proxy HTTP access through Squid $nat -A OUTPUT -m owner –uid-owner 13 -j ACCEPT $nat -A OUTPUT -p tcp –dport 80 -j REDIRECT -p tcp –to-port 3128
# Reject HTTPS $filter -A OUTPUT -m owner –uid-owner 13 -j ACCEPT $filter -A OUTPUT -p tcp –dport 443 -j REJECT
http://sylvarwolflinux.wordpress.com/2007/12/18/installing-squid-proxy-server-in-ubuntu/
Squid is a proxy http server that speeds up getting pages from the internet by keeping copies of commonly accessed pages or graphics instead of downloading them each time. To install it:-
- From a root terminal type apt-get install squid
- Open gedit /etc/squid/squid.conf
3. Find the TAG: visible_hostname and after the comments section add visible_hostname <hostname> where <hostname> is your machine’s hostname.
4. Check http_port is either set to 3128 or a port number that you can remember for configuring your browser.
- Close and save
- Type adduser squid and specify a password
- Restart squid by typing: /etc/init.d/squid restart
- Stop the service by typing /etc/init.d/squid stop
9. Test it in debug mode by typing squid -z (which creates the cache files)
- Type squid -NCd10 to test squid in debug mode and leave it running.
11. Open Firefox and type the URL localhost:3128 or whatever port you chose. It will fail to retrieve a page, but at the bottom it will confirm that the error is generated by squid.
- Back at the Terminal type CTRL-C to cancel the debug mode
13. Start squid for real with /etc/init.d/squid start. It will start automatically from now on.
14. To configure Firefox to use squid, go to Edit>Preferences and click Advanced.
15. Click Network>Settings and then Manual Proxy Configuration. For http proxy, enter localhost and for port 3128 (or whichever port you chose).
- Then click OK and close the Preferences dialogue.
- Now go to any webpage. If you get the page, it’s working!
Programs for Study¶
- algotutor
- fraqtive
- golly
- gplanarity
- graphthing
Starting with Tmux¶
- Start by typing tmux
- CNTL+B is the hotkey for tmux, just as CTRL+A was for screen.
- CNTL+B is remapped to CNTL+A
- CNTL+A ? will give you help for different things.
- CNTL+A c will create a new window.
- CNTL+A x will kill the window.
- CNTL+A <num> will help you move within those windows.
This is enough to get you started with tmux.
