Funny !!!

valgrind: the 'impossible' happened:
Killed by fatal signal
==4660== at 0x3802088D: vgPlain_arena_malloc (m_mallocfree.c:190)
==4660== by 0x38035516: vgPlain_cli_malloc (replacemalloc_core.c:101)
==4660== by 0x380022F5: vgMemCheck_malloc (mc_malloc_wrappers.c:182)
==4660== by 0x38035BA7: do_client_request (scheduler.c:1158)
==4660== by 0x380372B1: vgPlain_scheduler (scheduler.c:869)
==4660== by 0x38051B59: run_a_thread_NORETURN (syswrap-linux.c:87)

sched status:
running_tid=1

Thread 1: status = VgTs_Runnable
==4660== at 0x4A05809: malloc (vg_replace_malloc.c:149)
==4660== by 0x4030B0: _readTime (commands.c:676)
==4660== by 0x402124: _processReceivedData (commands.c:361)
==4660== by 0x401EEC: _performReceive (commands.c:322)
==4660== by 0x401809: _performCommand (commands.c:225)
==4660== by 0x401340: commandCenter (commands.c:163)
==4660== by 0x400D39: main (Hj1.c:63)

strlen @ C

Take care of bastard, strlen in C does not take the last ending sign.

DESCRIPTION
The strlen() function calculates the length of the string
s, not including the terminating '\0' character.

Jump to line number n

:n ---> Jump to line number n. For example, to jump to line 42, you'd type :42

Controlling Ctrl^C for quiting program, C programing

If you want Ctrl^C, not to jump out of program right away and give you a chance to save stuffs and get a backup here is the C code for it :

#include
#include
#include


void exit_program(int sig) {
printf("Wake up call ... !!! - Catched signal: %d ... !!\n", sig);
/* DO YOUR STUFFS BEFOR QUITING, if you dont want to wait for the 2nd
Ctrl^C from user you can just have the next commented line :*/
//exit(0);
(void) signal(SIGINT, SIG_DFL);//You need 2nd Ctrl^C to quit
}

int main(void) {
(void) signal(SIGINT, exit_program);
/* waits to read your signal(first Ctrl^C) while running rest of your code, on
Ctrl^C pressed will jump to exit_program method*/

while(1)
printf("I wanna catch Ctrl + C\n"), sleep(1);

return 0;
}

Giving your screen session a name

You can use screen -S name or (inside running session) - Ctrl+A :sessionname name

Vim/Vi command sheet

Cursor movement

• h - move left
• j - move down
• k - move up
• l - move right
• w - jump by start of words (punctuation considered words)
• W - jump by words (spaces separate words)
• e - jump to end of words (punctuation considered words)
• E - jump to end of words (no punctuation)
• b - jump backward by words (punctuation considered words)
• B - jump backward by words (no punctuation)
• 0 - (zero) start of line
• ^ - first non-blank character of line
• $ - end of line
• G - Go To command (prefix with number - 5G goes to line 5)

Note: Prefix a cursor movement command with a number to repeat it. For example, 4j moves down 4 lines.

Insert Mode - Inserting/Appending text

• i - start insert mode at cursor
• I - insert at the beginning of the line
• a - append after the cursor
• A - append at the end of the line
• o - open (append) blank line below current line (no need to press return)
• O - open blank line above current line
• ea - append at end of word
• Esc - exit insert mode

Editing

• r - replace a single character (does not use insert mode)
• J - join line below to the current one
• cc - change (replace) an entire line
• cw - change (replace) to the end of word
• c$ - change (replace) to the end of line
• s - delete character at cursor and subsitute text
• S - delete line at cursor and substitute text (same as cc)
• xp - transpose two letters (delete and paste, technically)
• u - undo
• . - repeat last command

Marking text (visual mode)

• v - start visual mode, mark lines, then do command (such as y-yank)
• V - start Linewise visual mode
• o - move to other end of marked area
• Ctrl+v - start visual block mode
• O - move to Other corner of block
• aw - mark a word
• ab - a () block (with braces)
• aB - a {} block (with brackets)
• ib - inner () block
• iB - inner {} block
• Esc - exit visual mode

Visual commands

• > - shift right
• < - shift left
• y - yank (copy) marked text
• d - delete marked text
• ~ - switch case

Cut and Paste

• yy - yank (copy) a line
• 2yy - yank 2 lines
• yw - yank word
• y$ - yank to end of line
• p - put (paste) the clipboard after cursor
• P - put (paste) before cursor
• dd - delete (cut) a line
• dw - delete (cut) the current word
• x - delete (cut) current character

Exiting

• :w - write (save) the file, but don't exit
• :wq - write (save) and quit
• :q - quit (fails if anything has changed)
• :q! - quit and throw away changes

Search/Replace

• /pattern - search for pattern
• ?pattern - search backward for pattern
• n - repeat search in same direction
• N - repeat search in opposite direction
• :%s/old/new/g - replace all old with new throughout file
• :%s/old/new/gc - replace all old with new throughout file with confirmations

Working with multiple files

• :e filename - Edit a file in a new buffer
• :bnext (or :bn) - go to next buffer
• :bprev (of :bp) - go to previous buffer
• :bd - delete a buffer (close a file)
• :sp filename - Open a file in a new buffer and split window
• ctrl+ws - Split windows
• ctrl+ww - switch between windows
• ctrl+wq - Quit a window
• ctrl+wv - Split windows vertically

Source : http://www.worldtimzone.com/res/vi.html

Write an array to file in C

int backItUp(){
FILE * hFile;
//************************
char *_fileName;
_fileName = getenv("USER");
char buffer[200];
struct timeval tv;
time_t curtime;
gettimeofday(&tv, NULL);
curtime=tv.tv_sec;
strftime(buffer,30,"%Y%m%d_%H%M",localtime(&curtime));
//"%m-%d-%Y %T"
strcat(_fileName,"_");
strcat(_fileName,buffer);
strcat(_fileName,".bak");
//*******************************
hFile = fopen( _fileName, "w");
if (hFile == NULL){
// Error, file not found
printf("*** Failed to open the file ***\n");
return FAILED;
}//end of if
else{
// Process & close file
int nWritten = fwrite(message, sizeof(SmsDBase), 200, hFile);
printf("*** Taking backup ***\n");
fclose(hFile);
}//end of else
return SUCCESS;
}//end of backItUp()

int readItUp(){
FILE * hFile;
hFile = fopen( ___fileName, "r");
if (hFile == NULL){
// Error, file not found
printf("*** Failed to open the file ***\n");
return FAILED;
}//end of if
else{
// Process & close file
int nRead = fread(message, sizeof(SmsDBase), 200, hFile);
fclose(hFile);
}//end of else
return SUCCESS;
}//end of _readItUp()

list of Vim commands

The list of Vim commands :

http://www.tuxfiles.org/linuxhelp/vimcheat.html

copying folder in Linux / Unix terminal

cp -r /original/dir /copied/dir

Saving and quiting at Vim

If like me you wonder how the hell to write in Vim, make sure you are in the insert mode(The mode that you can actually write). You can do that by pressing i.

After finishing, you are supposed to save what you have written. So you press Esc button and then write :w. Then you can simply write :q to quit.

Pay attention that you can write commands(:w, :q, ...) in the command line and you can go to command line by pressing Esc button in Vim.

Good luck, it is a powerful editor, but as me, you got a long way a head to learn how to work with it.

Showing Line Number while editing a file in Vi or Vim

While editing a document at Unix/Linux, press Esc button type

:set number

to have line numbers beside your editor. If you are tired of line numbers, enter the following to turn them off:

:set nonumber

Crazy about old games ? Try DosBox

DOSBox is an emulator which emulates an IBM PC compatible computer running MS-DOS. It is intended especially for use with old PC games. DOSBox is free software.

instanceof example in Java

public class MainClass {
public static void main(String[] a) {

String s = "Hello";
if (s instanceof java.lang.String) {
System.out.println("is a String");
}
}

}