tab as sort's field-separator

Hi,

It appears that one can't specify just a tab (a tab and only a tab) as
sort's field-separator.  As shown below, the UNIX example does it
right whereas the Linux example fails.

Is this a bug/limitation or did I miss the correct way to do this?

I can work around this in bash using:
	TAB=`echo -e "\t"`
	sort -t"$TAB" ...

but this trick doesn't work with tcsh using:
	setenv TAB `/bin/echo -e "\t"`

Must be the different way expressions are expanded with quotes in the
two shells.

Jim


$ cat /tmp/x
2	x, a1
2	x, b
1	x, a2

NB: Each line consists of <digit><tab>x,<space><letter><optionaldigit>

***

RH 7.2, textutils-2.0.14-2

$ sort -t'\t' -u -k2,2 -k1,1 /tmp/x
sort: multi-character tab `\t'

***

Compaq Tru64 UNIX V5.1 (Rev. 732)

% sort -t'\t' -u -k2,2 -k1,1 /tmp/x
2       x, a1
1       x, a2
2       x, b

***