MODPKT

Format: MODPKT[/LOG] "input_file output_file"

The command places the user in a "mini-editor" which knows the structure of the file and the locations and descriptions of the data items in the file and allows the user to locate and modify the values within the file on an item by item basis. Explanations of the commands available within the mini-editor can be obtained by typing "H" for help when prompted for input. See help on 'Mini-editor_commands' for a summary.

Inputs

An input file with an extension of .SHX, .ULX, or .EIX. Based on the extension the file is assumed to be an SHP, UDL, or EIF. If the file extension is not one of these standard extensions, the program prompts the user for the file type which the input file is assumed to be.

"output_file" with the modifications.

The input file is assumed to be present in the user's default directory and the output file is also created there.

Input_file

This is the input filename. The file extension is used by the program to determine the file type (.SHX indicates SHP, .ULX indicates UDL, and .EIX indicates EIF); if the input file has a non-standard extension,the program will prompt for the file type.

This is the output file name to be generate

/LOG

/LOG (D)

/NOLOG

The /LOG qualifier, if present, causes every change the user makes to the file being modified to be logged to the Information Set's trailer file. This logging can be turned off by specifying /NOLOG. The default value is /LOG.

The MODPKT command begins by displaying the name, location, description, and current value of the first data item in the file. It then asks the user for instructions. The user can either enter a new value for this data item (by simply typing the new value) or move on to a different data item by entering one of the following commands:

H to ask for help

to advance to next data item

S n to skip forward n data items

Y n to go to data item at byte n

M name to jump forward to data item with mnemonic = "name"

J name to jump forward to data item with field name = "name"

T to back up to the top of this packet

N to move on to next packet

P n to move on to packet n

X to exit the program

Q to quit/abort

R to restore original value of this data item

SHXMAKE Convert the SHX_DUMP output from ASCII back to its binary form

BINARY A binary file editor: modify individual bytes of a .PKX file

$ modpkt "Y0AN0405T.SHX temp.shx"

This command invokes the MODPKT editor for the file and displays the first mnemonic in the file:

__________________________________________________________________

File: Y0AN0405T.SHX Record: 1

Start byte, bit: ( 1, 0) End byte, bit: ( 1, 7)

Mnemonic Value Format Field Name

__________________________________________________________________

00 Z2.2 SOURCE_ID

A command like "M YCLKMON" jumps to that mnemonic to allow the user to enter a new value for that mnemonic.

Enter new value or command: M YCLKMON

__________________________________________________________________

File: Y0AN0405T.SHX Record: 1

Start byte, bit: ( 304, 6) End byte, bit: ( 304, 6)

Mnemonic Value Format Field Name

__________________________________________________________________

YCLKMON 0 Z1.1 MICROPROCESSOR CLOCK