5 ms·

>In most Unix utilities, “long lines are silently truncated”. This is not acceptable in a GNU utility. Would be interested to know examples for this.

• bigbillheck 5y ago
  Old versions of sort: http://man.cat-v.org/unix_7th/1/sort http://man.cat-v.org/unix_7th/1/sort Unix utilities in the old days weren't all that great. One example I've posted about here before is how mv would refuse to move files across filesystem boundaries (because it's not a 'move', it's a 'copy and delete', so you had to use cp and rm instead).
  • asicsp 5y ago
    Thanks. >BUGS Very long lines are silently truncated. And didn't know that about `mv`, good to know.
    • hulitu 5y ago
      It is a good practice to use cp + (verify) + rm instead of mv. Especially when the data is important.
      • cozzyd 5y ago
        or rsync --remove-source-files
  • l33t2328 5y ago
    mv doesn’t do that anymore. Is there any reason to use cp and rm instead of mv today?
    • _ZeD_ 5y ago
      paranoia... you could do cp + diff md5/sha1sum src/dst + rm
• jomar 5y ago
  Some current vendor versions of awk have astonishingly short line length limitations. See e.g. (especially the latter): https://github.com/samtools/samtools/pull/1165 https://github.com/samtools/samtools/pull/1165 https://github.com/samtools/htscodecs/pull/22 https://github.com/samtools/htscodecs/pull/22 which work around limitations in the default system awk on Solaris/OpenIndiana/whatever the remnants of SunOS are called these days…
• c0l0 5y ago
  Just a few weeks ago, I fixed a problem in an internal tool (that still also runs on an ancient Solaris 10 box) by switching from `awk` to `gawk`, since the former would briefly whine on stderr and quit whenever a line in its input would contain too many fields. A recent change had managed to break that undocumented barrier. In this case there's at least no silent breakage involved, but the badly written shell script that called it did not bother to check for that condition, and a fair number of heads were scratched for a while as a consequence.
  • andylynch 5y ago
    Yep. When we did Solaris installs GNU coreutils and friends were high on the list. Incidentally nice to see sunfreeware.com is still going!
• astrobe_ 5y ago
  The whole paragraph: > Avoid arbitrary limits on the length or number of any data structure, including file names, lines, files, and symbols, by allocating all data structures dynamically. In most Unix utilities, “long lines are silently truncated”. This is not acceptable in a GNU utility. ... goes against MISRA C, which certainly is preferable in the domain I work, embedded systems - because dynamic allocations all over the place are a recipe for CVEs.
  • jcelerier 5y ago
    GNU is about making software for the end-user, that's the opposite of what MISRA is about
    • astrobe_ 5y ago
      https://www.cvedetails.com/vulnerability-list/vendor_id-72/GNU.html https://www.cvedetails.com/vulnerability-list/vendor_id-72/G... A significant number of these CVEs are related to dynamic memory allocation (double-free, use-after-free). Probably not all are the result of that piece of advice and probably some of those memory allocations were necessary, but since this class of errors is common in C/C++, I believe it is really not a good idea to encourage people to point the gun right to their feet. On a side note, please explain to me how this is end-user oriented in a system where the convention is that a program ends silently when everything went smoothly: > In error checks that detect “impossible” conditions, just abort. There is usually no point in printing any message [...] Explain the problem with comments in the source.
      • jcelerier 5y ago
        if everything went smoothly likely the program had some useful output (e.g. grep, awk, sed). If it failed then I'd just run `coredumpctl gdb` ? (and ... abort isn't silent ? here's what I get if something aborts here: https://imgur.com/a/69eF73w https://imgur.com/a/69eF73w)