On 2008-03-23 00:06, Nicholas Robinson wrote:
On Saturday 22 March 2008 21:38:46 Nicholas Robinson wrote:
On Saturday 22 March 2008 21:18:11 Amadeus W.M. wrote:
You would think specifying tab as a field separator for sort would work
like this:
cat file | sort -k 3 -t "\t"
It doesn't:
sort: multi-character tab `\\t'
So after a little search and some trial and error I got this to work:
cat file | sort -k 3 -t "`/bin/echo -e '\t'`"
For my own curiosity, can someone please illuminate me as to why the
first incantation does not work as expected? Is there a more natural way
to specify \t other than echo?
Take the double quotes out in your first attempt. So command becomes
cat file | sort -k 3 -t \t
Nick
Sorry, I was a little bit quick off the mark. The \t doesn't yield a tab
character (see below) as you were implying and I went along with in the first
example! If you take the double quotes out as I suggested, then the field
separator becomes the character t!
I think (being a little more cautious this time!) that you want:
\ followed by Ctrl V followed by Ctrl I
If I remember correctly, sort interprets a tab as a default field separator
anyway.
As to the why: it is because the -t takes an argument which is a character.
Putting double quotes around it stops the \ being elided and so \t as two
characters \ and t are presented to sort which is expecting only one
character. Hence its moan. Try echo "\t" and you will see what I mean.
In my second attempt above, the Ctrl V stops the tab character (Ctrl I) being
expanded on the command line and the \ joins the tab character to the t.
HTH
Nick
Easier:
sort -k 3 -t $'\t'
See `man bash' and look for $'string'.
--
Sjoerd Mullender
