gdb executes a ~/.gdbinit file when it starts, if present; you should be able to add the line

    set disassembly-flavor intel

to it.

[![enter image description here][1]][1]

IF I wanted a picker, for states/provinces, i haven&#39;t seen an example, but I mocked up shown above, a picker for US/Can/Mex. wondering can you dynamically switch the NSMutableArray for the UIPickerView and then have it somehow reload each time you click on US/Can/Mex buttons???  How do I go about doing this.  What approach do I take.  Looking for someone to point a beginner for a clue in the right direction.  

 


  [1]: https://i.stack.imgur.com/5ATRG.jpg

How do I reload/refresh the UIPickerView (with new data array) based on button press?

How can I create a list out of all of the files in a specific directory in Clojure? Do I have to resort to calling Java or can Clojure handle this natively?

Listing files in a directory in Clojure

How can I permanently change the disassembly flavor in GDB.  I tried:`set disassembly-flavor intel` in GDB, but when I fire up GDB later it still has the att flavor.

Permanently Change Disassembly Flavor in GDB

<p>How can I permanently change the disassembly flavor in GDB.  I tried:<code>set disassembly-flavor intel</code> in GDB, but when I fire up GDB later it still has the att flavor.</p>


I have following string:

    {&quot;_id&quot;:&quot;scheme_version&quot;,&quot;_rev&quot;:&quot;4-cad1842a7646b4497066e09c3788e724&quot;,&quot;scheme_version&quot;:1234}

and I need to get value of &quot;scheme version&quot;, which is 1234 in this example.

I have tried 

    grep -Eo &quot;\&quot;scheme_version\&quot;:(\w*)&quot;

however it returns 

    &quot;scheme_version&quot;:1234

How can I make it? I know I can add **sed** call, but I would prefer to do it with single grep.

grep: group capturing

Say you have a txt file, what is the command to view the top 10 lines and bottom 10 lines of file simultaneously?

i.e. if the file is 200 lines long, then view lines 1-10 and 190-200 in one go. 

unix - head AND tail of file

In a C program if we want to give some input from terminal then we can give it by:

    int main(int argc, char *argv[])

In the same way, if we want to get return value of `main()` function then how can we get it?

In each `main()` we write `return 1` or `return 0`; how can I know what my `main()` has returned at terminal?


**Edit:1**

I get it that by `echo $?` we can get the return value of `main()` but it only allows me to return a value less then 125 (in Linux) successfully. A return value more than that cannot be be successfully received by the `$ variable` so 

**why is `int` the return type of `main()`? Why not keep it `short int`?**

**Edit2**

From where can I find out the meaning of the error code if `main()` returns a value greater than 125?

How can I get what my main function has returned?

Given a file with data like this (i.e. stores.dat file)

    sid|storeNo|latitude|longitude
    2|1|-28.03720000|153.42921670
    9|2|-33.85090000|151.03274200


What would be a command to output the number of column names?

i.e. In the example above it would be 4. (number of pipe characters + 1 in the first line)

I was thinking something like:

    awk &#39;{ FS = &quot;|&quot; } ; { print NF}&#39; stores.dat

but it returns all lines instead of just the first and for the first line it returns 1 instead of 4

unix - count of columns in file

Given a file with data like this (ie stores.dat file)

    sid|storeNo|latitude|longitude
    2tt|1|-28.0372000t0|153.42921670
    9|2t|-33tt.85t09t0000|15t1.03274200


What is the command that would return the number of occurrences of the &#39;t&#39; character per line?

eg. would return:

    count   lineNum
       4       1
       3       2
       6       3



------------------------------------
Also, to do it by count of occurrences by field what is the command to return the following results? 

eg. input of column 2 and character &#39;t&#39;

    count   lineNum
       1       1
       0       2
       1       3


eg. input of column 3 and character &#39;t&#39;

    count   lineNum
       2       1
       1       2
       4       3

Count occurrences of character per line/field on Unix

I saw some x86 assembly in Qt&#39;s source:

    q_atomic_increment:
    	movl 4(%esp), %ecx
    	lock 
    	incl (%ecx)
    	mov $0,%eax
    	setne %al
    	ret
    
    	.align 4,0x90
    	.type q_atomic_increment,@function
    	.size	q_atomic_increment,.-q_atomic_increment

1. From Googling, I knew `lock` instruction will cause CPU to lock the bus, but I don&#39;t know when CPU frees the bus?

2. About the whole above code, I don&#39;t understand how this code implements the `Add`?


What does the &quot;lock&quot; instruction mean in x86 assembly?

Is there syntax highlighting for assembly in Sublime Text 2?

I&#39;m having some trouble understanding the difference between caller and callee saved registers and when to use what. 

I am using the MSP430
:

procedure:

    mov.w #0,R7 
    mov.w #0,R6 
    add.w R6,R7 
    inc.w R6 
    cmp.w R12,R6 
    jl l$loop 
    mov.w R7,R12
    ret

the above code is a callee and was used in a textbook example so it follows the convention. R6 and R7 are callee saved and R12 is caller saved. My understanding is that the callee saved regs aren&#39;t &quot;global&quot; in the sense that changing its value in a procedure will not affect it&#39;s value outside the procedure. This is why you have to save a new value into the callee reg at the beginning.

R12, the caller saved is &quot;global&quot;, for lack of better words. What the procedure does has a lasting effect on R12 after the call.

Is my understanding correct? Am I missing other things?

What are callee and caller saved registers?

I want to write a small low level program. For some parts of it I will need to use assembly language, but the rest of the code will be written on C/C++.

So, if I will use GCC to mix C/C++ with assembly code, do I need to use AT&amp;T syntax or can 
I use Intel syntax? Or how do you mix C/C++ and asm (intel syntax) in some other way?

I realize that maybe I don&#39;t have a choice and must use AT&amp;T syntax, but I want to be sure..

And if there turns out to be no choice, where I can find full/official documentation about the AT&amp;T syntax?

Thanks!

Can I use Intel syntax of x86 assembly with GCC?

I am using the `otool`, `nm` and `Fraise` text editor to disassemble the `Mach-o` binaries. My workflow at this point is pretty straightforward:

&lt;ol&gt;
1. List the existed symbols.
&lt;/ol&gt;

    nm -g

&lt;ol&gt;
2. Get the disasm code. &lt;br/&gt;
&lt;/ol&gt;

    otool -vt

&lt;ol&gt;
3. Copy and paste this output to a text file.
&lt;/ol&gt;

&lt;ol&gt;
4. Read and comment the codes in the text editor :)
&lt;/ol&gt;

I am looking for the tools that simplify the working with disasm code on `Mac OS X`.

What is your favorite disassembler tool in Mac OS X?

I&#39;m trying to inspect a buffer which contains a binary formatted message, but also contains string data. As an example, I&#39;m using this C code:

    int main (void) {
        char buf[100] = &quot;\x01\x02\x03\x04String Data\xAA\xBB\xCC&quot;;
    
        return 0;
    }

I&#39;d like to get a hex dump of what&#39;s in `buf`, of a format similar to `xxd` (I don&#39;t care if it&#39;s an exact match, what I&#39;m really looking for is a hex dump side by side with printable chars).

Inside GDB I can use something like:

    (gdb) x /100bx buf
    0x7fffffffdf00: 0x01    0x02    0x03    0x04    0x53    0x74    0x72    0x69
    0x7fffffffdf08: 0x6e    0x67    0x20    0x44    0x61    0x74    0x61    0xaa
    0x7fffffffdf10: 0xbb    0xcc    0x00    0x00    0x00    0x00    0x00    0x00
    0x7fffffffdf18: 0x00    0x00    0x00    0x00    0x00    0x00    0x00    0x00
    0x7fffffffdf20: 0x00    0x00    0x00    0x00    0x00    0x00    0x00    0x00
    0x7fffffffdf28: 0x00    0x00    0x00    0x00    0x00    0x00    0x00    0x00
    0x7fffffffdf30: 0x00    0x00    0x00    0x00    0x00    0x00    0x00    0x00
    0x7fffffffdf38: 0x00    0x00    0x00    0x00    0x00    0x00    0x00    0x00
    0x7fffffffdf40: 0x00    0x00    0x00    0x00    0x00    0x00    0x00    0x00
    0x7fffffffdf48: 0x00    0x00    0x00    0x00    0x00    0x00    0x00    0x00
    0x7fffffffdf50: 0x00    0x00    0x00    0x00    0x00    0x00    0x00    0x00
    0x7fffffffdf58: 0x00    0x00    0x00    0x00    0x00    0x00    0x00    0x00

which is fine, but it&#39;s hard to pick out strings that way... or I can use

    (gdb) x /100bs buf
    0x7fffffffdf00:  &quot;\001\002\003\004String Data\252\273\314&quot;
    0x7fffffffdf13:  &quot;&quot;
    0x7fffffffdf14:  &quot;&quot;
    0x7fffffffdf15:  &quot;&quot;
    0x7fffffffdf16:  &quot;&quot;
    0x7fffffffdf17:  &quot;&quot;
    ...

which makes it hard to read the binary part... the actual messages I&#39;m dealing with have plenty of ascii nul&#39;s in them, too, so really it just looks like a mess.

The best I can come up with is to do this:

    (gdb) dump binary memory dump.bin buf buf+100

and then

    $ xxd dump.bin
    0000000: 0102 0304 5374 7269 6e67 2044 6174 61aa  ....String Data.
    0000010: bbcc 0000 0000 0000 0000 0000 0000 0000  ................
    0000020: 0000 0000 0000 0000 0000 0000 0000 0000  ................
    0000030: 0000 0000 0000 0000 0000 0000 0000 0000  ................
    0000040: 0000 0000 0000 0000 0000 0000 0000 0000  ................
    0000050: 0000 0000 0000 0000 0000 0000 0000 0000  ................
    0000060: 0000 0000                                ....

but that&#39;s a pain to do that every time. I figured somebody out there has wanted this before, so wondering if anybody has found a way to do it inside gdb.  Plus you lose the addresses from the original memory this way.

I&#39;m using GDB 7.4 with python support built in, so I&#39;m open to the idea of using a pretty printer or similar, but I don&#39;t know how to set that up.


Memory dump formatted like xxd from gdb

I keep getting this error mesage when trying to add a breakpoint in gdb.

I&#39;ve used these commands to compile:

    gcc -g main.c utmpib2.c -o main.o
    and:
    cc -g main.c utmpib2.c -o main.o
    and also:
    g++ -g main.c utmpib2.c -o main.o

I also tried &quot;-ggdb&quot; instead of &quot;-g&quot; and I still get that error message.

I then execute gdb:

    $gdb

In gdb:

    (gdb)exec-file main.o
    (gdb)break 59
    No symbol table is loaded. Use the &quot;file&quot; command.



gdb: &quot;No symbol table is loaded&quot;

Suppose that

    (gdb) print *this

resulted in 20 lines of output. Yes, there would be `Type &lt;return&gt; to continue, or q &lt;return&gt; to quit`, but I&#39;d like to scroll back to the top after I got to the bottom of the output.

I don&#39;t think http://sourceware.org/gdb/onlinedocs/gdb/TUI-Keys.html answers my question. It states

&gt; &amp;lt;PgUp&amp;gt; &lt;br&gt;
&gt; Scroll the active window one page up.

but when the focus is on the command window, &lt;kbd&gt;PgUp&lt;/kbd&gt; rewinds the command history, instead of scrolling back in the command window. Is it only me who suffers from this behavior?

I&#39;m using [PuTTY][1] in order to SSH to Red Hat Linux (if this makes any difference).

  [1]: http://en.wikipedia.org/wiki/PuTTY


How can I scroll back in GDB&#39;s command window in the TUI mode?

Basically, I want to get `typeid(*this).name()`, i.e. the real type of `this`.

I want to get this in GDB (without modifying the source code). I tried `print typeid(*this)` but it says that `typeid` is unknown (because I didn&#39;t included it there in the source file).


gdb: show typeinfo of some data

Currently, when I print the value of a variable `v` in GDB (`print v`) I get an integer.

Is it possible to have GDB print such integer variables in hexadecimal or binary?


Content Type	Original Author	Original Content on Stackoverflow
Question	HighLife	View Question on Stackoverflow
Solution 1 - Linux	DSM	View Answer on Stackoverflow

Permanently Change Disassembly Flavor in GDB

Linux Problem Overview

Linux Solutions

Solution 1 - Linux

Listing files in a directory in Clojure

How do I reload/refresh the UIPickerView (with new data array) based on button press?

Attributions