On Monday 17 Jan 2011, Ralph Corderoy wrote:
> > Now my understanding of cat goes back to a noddy Unix course about
> > 15-20 years ago, but I always thought the 'cat' stood for 'catalogue'
> > and was used to list the content of a text file. Having looked at
> > http://unixhelp.ed.ac.uk/CGI/man-cgi?cat though, I now know that it
> > stands for concatenate
>
> That man page is wrong! It doesn't stand for concatenate, else it would
> be con(1), not cat(1). :-) It stands for catenate, always has done.
> Here's the man page from the 7th Edition of Unix from Bell Labs.
>
> wget -qO- http://www.cs.bell-labs.com/7thEdMan/vol1/man1.bun |
> sed -n '/^-\.TH CAT/,/GO\.SYSIN DD/s/-//p' |
> nroff -man
I never even knew that catenate was a word ;-)
> Back to Terry:
> > My flawed experience told me that cat was used with text files and the
> > man page I found earlier certainly didn't make it clear that any files
> > could be cat'd together. Whether that makes any sense clearly depends
> > on what those files are, but having understood that fact I was able to
> > get to the next step; gzip files wouldn't be broken because of the way
> > they are structured.
>
> Unix doesn't fundamentally distinguish between text and binary files at
> the kernel level as other OSes do. They're just a sequence of zero or
> more bytes. Unless stated otherwise, assume a command doesn't care
> whether the bytes could be considered as a LF-terminated sequence of
> zero or more lines of printable bytes. Not having the text/binary
> distinction is quite an advantage compared to, e.g. DOS, which also has
> its ASCII SUB, Ctrl-Z, file terminating byte; awful, mixing data and
> metadata.
I knew that really :-) The trouble is that I had only ever used cat with text
files, so it never even occured to me, in this context, that a file is a file
and it doesn't matter what is in it.
--
Terry Coles
64 bit computing with Kubuntu Linux
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