fireyfly / hexd Goto Github PK

There is some kind of interplay between -w and the chunk size that causes hexd to print misaligned lines in some cases.

E.g. hexd -w 28 -g 4 $(which hexd) shows this misalignment around BUFSIZ-sized chunks:

    ...
    03b8  63 00 00 00  12 00 00 00  00 00 00 00  00 00 00 00  00 00 00 00  00 00 00 00  45 01 00 00  c... .... .... .... .... .... E...
    03d4  20 00 00 00  00 00 00 00  00 00 00 00  00 00 00 00  00 00 00 00  a8 00 00 00  12 00 00 00   ... .... .... .... .... ¨... ....
    03f0  00 00 00 00  00 00 00 00  00 00 00 00  00 00 00 00                                         .... .... .... ....               
    0400  cc 00 00 00  12 00 00 00  00 00 00 00  00 00 00 00  00 00 00 00  00 00 00 00  89 00 00 00  Ì... .... .... .... .... .... ‰...
    041c  12 00 00 00  00 00 00 00  00 00 00 00  00 00 00 00  00 00 00 00  e4 00 00 00  12 00 00 00  .... .... .... .... .... ä... ....
    ...

This appears to "only" be cosmetic, in that it doesn't look like the data being printed is corrupted (at least from first glance); no data seems to be missing/duplicated. A similar issue also affects pixd (with -w 28).

The issue appears to be that BUFSIZ-sized chunks are handled at a time, and each row only contains printed bytes from the same chunk. Thus, if the line width isn't a multiple of the chunk size, the last line within that chunk will be incomplete (in this case only displaying 16 bytes).

Reported by @zgrep.

Sometimes it's useful to see every byte of a file, and disable autoskip for that.

Currently, hexd unconditionally defaults to colourised output, and has the -p flag for turning colour off. A better option would be to default to detecting colour based on tty-ness (a la GNU --color=auto) and have explicit flags for turning colour on or off.

• Could do GNU-style --color[=WHEN]. GNU ls defaults to no colours, but I think defaulting to colours if output is a tty is okay.
• Could just default to auto and have explicit options. Which single-char flags would be appropriate for "no colours" and "yes colours"?
• Either way, later flags should supersede earlier ones, to allow for alias hexd=hexd -p or similar.

Same as FireyFly/pixd#3, it'd be great if Makefile had an 'install' option to install the binary, and the man page.

Old hexd had this feature: default to automatically determining a width based on tty width (i.e. $COLUMNS, tput cols). It would look at the -g option and use the maximum number of groups per line that would fit. The upside is better terminal size utilization, but the downside is that a width of e.g. 0x18 might be less convenient than 0x10 (the usual default) because it offsets every other line, kinda.

I'm not sure I really liked this feature, but as I'm undecided I'm opening this issue to not forget to ponder it in the future. It could always be added as an optional thing controlled by an environment variable, but OTOH adding unwanted features seems like a recipe for feature creep/just general untidyness..