The -F option for awk is more clever than the manual says. Do we want
the behavior, or is the manual right?
I noticed a working bug in a little script that led to this suprising
result:
$ echo foo | awk -F t '{print FS}' | hexdump -C
00000000 09 0a |..|
00000002
If the argument to the -F option is
t
awk assumes you meant '\t' and sets the FS variable to TAB. That's not
mentioned in the manual. Apparently the only way to use the letter 't'
as a field separator is with the regex '[t]'.
I'm sure that's meant to help the clueless, because I found myself
taking advantage of it in my own script
| grep -f /etc/whitelist.dat \
| awk -F\t '{print $2}' \
| sed s'/[<>]//g' \
even though I had no right to expect it to work.
This appears to be the only specially treated character. The relevant
function is setfs(). It has a pithy comment inside conditional
compilation:
static char *
setfs(char *p)
{
#ifdef notdef
/* wart: t=>\t */
if (p[0] == 't' && p[1] == 0)
return "\t";
else
#endif
if (p[0] != 0)
return p;
return NULL;
}
I find no support for this "wart" at the open group
(http://pubs.opengroup.org/onlinepubs/9699919799/utilities/awk.html).
Maybe we should just change the Makefile?
--jkl
