sudo -s
echo PACKAGE_NAME hold | dpkg –set-selections

To verify the settings for a package to:

sudo -s
dpkg –get-selections PACKAGE_NAME

To re-enable a package to be upgraded do:

sudo -s
echo PACKAGE_NAME install | dpkg –set-selections

More info can be found here:
https://help.ubuntu.com/community/PinningHowto

1. Copy your .Xdefaults file to C:\Users\USERNAME\AppData\ Local\StarNet\X-Win32\Xdefaults. Where USERNAME is your Windows user name.
2. Disable the Set Xresource Defaults option in the X-Win32 X-Config’s Window tab.

This could be useful when you want to grep for TAB or split lines of a TAB separated file with cut.

Old URL: https://www.oldrepo.com/svn/
New URL: https://www.newrepo.com/svn/

svn switch –relocate https://www.oldrepo.com/svn https://www.newrepo.com/svn

See svn switch in Version Control with Subversion book for more details.

Error: No word lists can be found for the language “en_US”.

when trying to start ispell (e.g., M-x ispell-buffer) from Emacs, then you need to install the aspell-en package:

sudo apt-get install aspell-en

• C-@ or C-Space — start selection (as usual)
• M-x delete-rectangle or C-x r d — delete the rectangle delimited by the start selection and the current cursor position
• M-x kill-rectangle or C-x r k — then you can use — M-x yank-rectangle or C-x r y
• M-x clear-rectangle or C-x r c — replace the contents of the rectangle with spaces
• M-x open-rectangle or C-x r o — insert spaces in the area and push the original contents to the right

#include <ext/numeric>
#include <vector>
…

std::vector<int> v(5);
__gnu_cxx::iota(v.begin(), v.end(), 0);

v will contain {0, 1, 2, 3, 4}.

For more information see sgi documentation

”.join(['&#%d;' % ord(ch) for ch in text])

For example if text=’mailto’ the output would be:

‘& #109;& #97;& #105;& #108;& #116;& #111;’

This might be useful in hiding email addresses in web pages.

Option “XkbOptions” “ctrl:swapcaps”

If you woud like to keep the Ctrl where it is and make Caps Lock act as a Ctrl also, you can add:

Option “XkbOptions” “ctrl:nocaps”

dd if=/dev/zero of=test100M.bin bs=100000000 count=1

where of is the output file and bs is its size in bytes.

template <class T>
class A {
…
template <class T>
friend void b(A<T> a);
} ;

Will confuse the compiler, as you use the same template name, T, for the class template and the function template type. What you need to do, it to use a different name for the function template type:

template <class T>
class A {
…
template <class V>
friend void b(A<V> a);
} ;

Notice that I used T for the class template type and V for the function template type.

echo myhost.com > /etc/hostname

will give you the following error:

-bash: /etc/hostname: Permission denied

Unfortunately, using:

sudo echo myhost.com > /etc/hostname

will give the same error.

The solution is to start bash as sudo and then give the entire command to bash as input:

sudo bash -c “echo myhost.com > /etc/hostname”

Or as one reader suggested:

echo myhost.com | sudo tee /etc/hostname

#include <algorithm>
#include <string>
…
std::string data = “Abc”;
std::transform(data.begin(), data.end(),
data.begin(), ::toupper);

For converting to lower case, you need to replace ::toupper with ::tolower.

Other C/C++ not so frequently asked questions.

replace(/^\s+|\s+$/g, ”)

By removing |\s+$ it will do a left trim only, and by removing ^\s+| it will do a right trim only (g is no longer necessary).

lpstat | grep Printer

C-q C-j

In function `std::basic_filebuf<char, ignorecase_traits>::uflow()'::
undefined reference to `std::basic_filebuf<char, ignorecase_traits>::
_M_underflow_common(bool)'

The solution is to add the following to one of your CC/CPP files:

struct cGet_M_underflow_common : std::basic_filebuf<char> {
  int_type mGet_M_underflow_common(bool b) {
    return _M_underflow_common(b);
  };
};

icfielbuf::int_type icfielbuf::_M_underflow_common(bool bump) {
  return reinterpret_cast<cGet_M_underflow_common *>(this)->
    mGet_M_underflow_common(bump);
};

M + l to change to lowercase all the letters from the cursor to the end of the word
M + u same meaning, but upercase
M + c same meaning, but capitalizes

Write:
ofstream file(“foo.txt”, ios::out | ios::binary);
unsigned e =101;
file.write(reinterpret_cast<char*>(&e), sizeof(unsigned));

Read:
ifstream file(“foo.txt”, ios::in | ios::binary);
unsigned e;
file.read(reinterpret_cast<char*>(&e), sizeof(unsigned));

More info:
http://courses.cs.vt.edu/~cs2604/spring06/binio.html
http://www.codersource.net/cpp_file_io_binary.html

If you want to set the default separator to “:” you need to do:

IFS=:

If you want to set is to newline, you can do it like this:

IFS=$’\x0a’

‘\x0a’ is the hexadecimal notation for newline or Ctrl-J.

A common pattern is to save the old separator before changing and restore it when you are done:

IFS_OLD=$IFS
IFS=:
…
IFS=$IFS_OLD

or more simple, just unset it when you are done:

IFS=:
…
unset IFS

C-x RET f unix

quota -v

The command will not display the correct information on the Linux systems.

The get the amount of free space on a shared disk, use, for example:

df -h /extra/rvernica0

\usepackage{fancyhdr}
\pagestyle{fancy}
\fancyhf{} % clear all header and footer fields
\fancyfoot[R]{\footnotesize Page \thepage\ of 2}
\renewcommand{\headrulewidth}{0pt}
\renewcommand{\footrulewidth}{0pt}

This will print the page number on the right side of the footer, smaller font and in the format “Page % of 2″.

more +N file | head -n 1

(transient-mark-mode t)

See also Delete selected text.

Here is what you have to do (we asume that lines that start with # are considered comments):

M-x conf-unix-mode RET
M-: (setq comment-start “#”) RET

SELECT datname FROM pg_database;

uname

E.g.,

uname -a

will print the kernel version.

ar rcs libfunc.a func1.o func2.o func3.o

To link the libary to your code you can use use:

g++ -o exe_file exe_file.o -L. -lfunc

#include <sstream>

int i = 5;
std::string s;
std::stringstream out;
out << i;
s = out.str();

Other C/C++ not so frequently asked questions.

(define-key html-mode-map (kbd “TAB”) ‘self-insert-command); # only in html-mode

If you don’t really want tabs, but spaces to be inserted whenever you press the TAB key, add this to your .emacs file:

(define-key html-mode-map (kbd “TAB”) ‘tab-to-tab-stop); # only in html-mode

Make sure to call the above function in a mode hook.

You might also want to edit the size of each tab, so use:

M-x edit-tab-stops

For more info:
http://www.student.northpark.edu/pemente/emacs_tabs.htm

char buffer[] = “Hi there!”;
int n = 2;
printf(“%.*s”, n, buffer); // outputs “Hi”

It will output only the first n number of characters form buffer.

info man_page
e.g., info read

If you need a specific section (e.g., man 2 read), you can use:

info “man_page(page_no)”
e.g., info “read(2)”

If you are inside info and you want to read a “man” page, you can use:

M-x man RET man_page or
M-x man RET “man_page(page_no)”

fcntl(file_desc, F_SETFL, O_NONBLOCK); // <fcntl.h>

class String {
char str[80];
operator char *() { return str; } // convert to char*
}

And the you can use it like this:

char *buf;
String s;
buf =s;

More here:
http://www.ee.cooper.edu/courses/course_pages/past_courses/EID151/CPP.html

nm object_file | grep symbol_name

sqlite database .dump > database.sql

To put the data into a SQLite database from a sql file use:

sqlite database < database.sql

I don’t think you’ll get ANSI color in your Emacs terminal unless you have this:

;; Add color to a shell running in emacs ‘M-x shell’
(autoload ‘ansi-color-for-comint-mode-on “ansi-color” nil t)
(add-hook ‘shell-mode-hook ‘ansi-color-for-comint-mode-on)

Then set the colors:

(custom-set-faces
;; custom-set-faces was added by Custom — don’t edit or cut/paste it!
;; Your init file should contain only one such instance.
‘(comint-highlight-prompt ((t (:foreground “white”)))))

template <class T>
T Add(T a, T b)
{
return a+b;
}

friend ostream& operator<<(ostream& out, const ClassName& object)
{
…
return out;
}

M-x set-variable<RET> indent-tabs-mode<RET> nil

Or in your .emacs file:

(setq-default indent-tabs-mode nil)

For more info:
http://www.student.northpark.edu/pemente/emacs_tabs.htm

target ... : variable-assignment

on a separate line by itself.

Example:

CC=gcc
...
prog: CC=g++
prog: prog.cpp
	${CC} -o prog prog.cpp

Found here:

http://www.gnu.org/software/make/manual/html_node/Target_002dspecific.html

plot … with boxes linetype 1 …

If you do not specify linetype 1, then the boxes are plotted with different line types.

set terminal postscript
set output test.eps
test

In the file test.eps you will have all the available line styles and fill patterns.

#!/bin/sh
## Bundle --  put listed files into a bundle on stdout which sh will unbundle
# From "The UNIX Programming Environment," by Brian Kernighan and
#   Rob Pike, Prentice Hall, 1984.
echo "# To unbundle, sh this file"
for i
do
  echo "echo $i 1>&2"
  echo "cat >$i <<'End of $i'"
  cat $i
  echo "End of $i"
done

xrdb -merge ~/.Xdefaults

in order for them to take effect.

In PuTTY go to Connection -> SSH -> X11, check the Enable X11Forwarding option, and in X display location field specify localhost:0.

Do not forget to enable X11Forwarding on sshd. To do that add X11Forwarding yes to /etc/ssh/sshd_config and restart sshd.

kill -1 PID

This gives the HUP (hung up) signal to the process.

To enable flyspell in text-mode add this in your .emacs file:

(dolist (hook ‘(text-mode-hook))
(add-hook hook (lambda () (flyspell-mode 1))))

M-x mode_name-mode

To set the default major mode, which initially is Fundamental, add the following to your .emacs file:

(setq default-major-mode ‘mode_name-mode)