On 02/06/2015 09:45 AM, Eric Blake wrote: > On 02/06/2015 09:23 AM, Pádraig Brady wrote: >> On 06/02/15 15:57, Tyler Beaver wrote: >>> I know this tool is probably note used as much anymore, but perhaps it >>> would be worth adding a flag for overriding the verbose output number >>> system for the values, or at any rate specifying that this output is in >>> octal, and not decimal or hexadecimal. >> >> Currently: offsets are decimal, differing bytes are octal: >> >> $ cmp -l <(echo 12345678abc) <(echo 12345678bbb) >> 9 141 142 >> 11 143 142
Another observation: Note that when mixed with --ignore-initial, we
behave as if offsets start from the point where we skipped to, rather
than the beginning of the file. Since -i is not required by POSIX, does
this always make the most sense?
$ cmp -l <(printf bbc) <(printf abd)
1 142 141
3 143 144
$ cmp -l -i1 <(printf bbc) <(printf abd)
2 143 144
and what happens when we use the two-offset form?
$ cmp -l -i2:1 <(printf abcd) <(printf bce)
2 144 145
$ cmp -l -i1:2 <(printf bce) <(printf abcd)
2 145 144
> That said, it might be worth patching 'cmp --help' to make it obvious
> that differing bytes are in octal values.
That is, instead of
-l, --verbose output byte numbers and differing byte values
maybe we could use:
-l, --verbose for each difference, output the decimal
offset and the differing octal values
Expanding that to two lines can be offset by compressing elsewhere:
-i, --ignore-initial=SKIP skip first SKIP bytes of both inputs
-i, --ignore-initial=SKIP1:SKIP2 skip first SKIP1 bytes of FILE1 and
first SKIP2 bytes of FILE2
feels long; how about:
-i, --ignore-initial=SKIP[:SKIP2] bypass SKIP bytes of FILE1, and
SKIP2 (default SKIP) bytes of FILE2
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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