vim ctags tags path

This line in your ~/.vimrc should help:

set tags=./tags,tags;$HOME

It tells Vim to look for a tags file in the directory of the current file, in the current directory and up and up until your $HOME (that's the meaning of the semicolon), stopping on the first hit.

golang win32 UI

https://github.com/lxn/walk

OR

https://github.com/AllenDang/gform

OR

https://github.com/andlabs/ui

USB terms

In the USB world, the most basic data transfer is done in packet, but to understand the on-the-wire protocol, there are other things to understand.

Packet
USB Packet types: (Source: http://www.usbmadesimple.co.uk/ums_3.htm)

PID Type	PID Name	PID<3:0>*
Token	OUT	0001b
	IN	1001b
	SOF	0101b
	SETUP	1101b
Data	DATA0	0011b
	DATA1	1011b
	DATA2	0111b
	MDATA	1111b
Handshake	ACK	0010b
	NAK	1010b
	STALL	1110b
	NYET	0110b
Special	PRE	1100b
	ERR	1100b
	SPLIT	1000b
	PING	0100b
	Reserved	0000b

Transaction: 
   
One transaction has 3 packets: Token + Data + Handshake for a successful transaction. (*). Nak and Stall error condition could happen after Token when no data is available.

There are 3 types of transactions: IN, OUT, SETUP

 *: For IN and OUT transactions used for isochronous transfers, there are only 2 packets; there is no handshake packet.

Transfer:
There are 4 types of transfer:

• Control 
• Interrupt
• Bulk
• Isochronous (such as audio data)

HID device only uses Control and Interrupt

Control transfer = 3 transactions: SETUP + IN/OUT DATA + STATUS(IN/OUT transaction)

Other transfers has just one transaction: IN/OUT data.

In general, you want to pay attention to Transfer or Transaction level, not packet level. 

prevent ssh client timeout

Add this in /etc/ssh/ssh_config for Linux and ~/.ssh/config for Mac:

Host *
ServerAliveInterval 120

linux cp without overwrite

You can use "-n" option.

If you are on a embedded linux box with busybox, it does not have that option. You can this instead:

false | cp -i source destination 2>/dev/null

Vim show C function name

Put this in your .vimrc file, and use key "f" to show current function name:

fun! ShowFuncName()
  let lnum = line(".")
  let col = col(".")
  echohl ModeMsg
  echo getline(search("^[^ \t#/]\\{2}.*[^:]\s*$", 'bW'))
  echohl None
  call search("\\%" . lnum . "l" . "\\%" . col . "c")
endfun
map f :call ShowFuncName() <CR>

golang combine static data (css/js/images/) with binary file

https://github.com/tiebingzhang/statik (zip the contents and compiled it into go source code, very small code base, this is a github fork with the slash fix)

https://github.com/jteeuwen/go-bindata

https://github.com/GeertJohan/go.rice (can either compile zip into go source, or append the zip to existing go EXE, more flexible but code base is a little larger)

script to detected unused C files

If you have a large project with a lot of C files, once you compiled them, you will end up with a lot of .o files. Then you can use the .o files to find out which .c files is not used (conditionally compiled/not compiled). To do this, follow the steps below:

1. cd subdir
2. ls -1 > ../1.out
3. gawk -f lsnu.awk ../1.out

The lsnu.awk script
{
        if ($1 ~ /\.c$/){
                cfiles[$1]=1;
                print $1;
                next;
        }
        if ($1 ~ /\.o$/){
                ofiles[$1]=1;
                #printf("%s\n",$1);
                next;
        }

}

END{
        printf("-------------\n");
        for ( i in  cfiles){
                f=i;
                gsub(/\.c$/,".o",i);
                if (ofiles[i]!=1){
                        printf("%s ",f);
                        }
        }
        printf("\n");
}