hasc - display a file in color coded hexadecimal and ASCII

Synopsis

hasc [options] [file name]
hasc --help
hasc --version

Description

The hasc utility lists its input as hexadecimal character codes, with the original ASCII characters displayed on the right. With the -c or --color option it will color code the characters. Each line begins with it's offset, also in hex. hasc can be used for looking at the structure of a binary file.

hasc is similar to the xxd(1) program, but both provide different options. The most notable option that hasc provides, and xxd doesn't, is the coloring of control codes, using the -c option. However, xxd can regenerate binary files from listings that look like its output, allowing you to use it as a simple binary file editor. hasc can't do that. The program hasci(1) (the extra âiâ stands for âinteractiveâ) can be used to explore a binary file interactively, using a similar format and color coding scheme as hasc.

hasc uses the file listed after it's options, if any, as input. If no file name is specified it uses its standard input. The special â--â option can be used to indicate the start of the file name, which is useful if the file begins with a â-â character.

The -c option works by causing hasc to generate VT control codes that instruct a terminal to display different parts of the text in different colors. These codes may not generate the desired output on all terminals. Piping the output of hasc into a pager like more(1) or less(1) will not work because these programs do not understand the control codes. The output of hasc can be redirected into a file and displayed in a web browser by converting it into HTML using the utility vt2html(1).

By default hasc does not display duplicate lines. If it finds that there are several consecutive lines which are identical then it will output the first one and then a line containing only an asterisk (*), in the same way as od(1) does. You can work out how many duplicate lines there were by comparing the address fields of the lines before and after the asterisk. The -v option makes hasc display duplicate lines in full, just as it does for od.

Note that characters which are not part of the normal printable ASCII range (32–126) are not printed in the ASCII part of the output, unless the -e option is used. Normally a dot (.) is used to represent a character that might otherwise be unprintable. With the -c option some other symbols are also used for certain control characters (see below).

Options

-a, --no-ascii

Suppress the ASCII characters on the right, making the output more like that of od.

-c, --color, --colour

Uses color coding by inserting VT control codes into the output. The address at the start of each line is colored yellow. Both the hex character codes and the ASCII characters are colored green if the character code is above the standard range of printable ASCII characters (127 and above), or red if it is a control code (below 32). When -c is turned on recognized control codes are given the following symbols in the ASCII part of the output:

0   null (0x00),
a   bell/alert (0x07),
b   backspace (0x08),
t   tab (0x09),
n   line feed/newline (0x0A),
v   vertical tab (0x0B),
f   form feed (0x0C),
r   carriage return (0x0D), and
e   escape (0x1B).

These are only used when coloring is turned on, because the red coloring is needed to distinguish them from normal letters. Blue is used for the asterisks showing duplicate lines.

-e, --extended-ascii

Print characters with codes above 126 in the ASCII display instead of replacing them with dots.

-g, --no-gaps

Suppress the gaps between the hex character codes.

-H, --help

Give a brief description of what hasc does, with a synopsis showing allowable options.

-h, --half-width

Print half length lines. This makes the output suitable for a 40 column display, by printing only 8 bytes of input per line of output. It also prints only one space (rather than 2) after the address field, unless the colon has been suppressed with the -o option.

-o, --no-colon

Suppress the colon after the address field and print a space instead.

-V, --version

Print the name and version number of the program.

-v, --output-duplicates

Suppress the asterisks that mark duplicate lines. With this option consecutive lines that are identical will be displayed in full.

Bugs

It assumes that the output device likes VT codes.

The yellow offset numbers don't show up very well on a white background.

Copying

Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies.

Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one.

Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice may be included in translations approved by the Free Software Foundation instead of in the original English.

Author

Geoff Richards <geoff@laxan.com>

http://ungwe.org/free_software/hasci/

Qef's Website