On Sun, Sep 3, 2017 at 5:06 PM, Mark Volkmann <r.mark.volkm...@gmail.com>
wrote:
> IIUC, there isn't a command in fish that can be used to compare two
> strings to see if one is greater than the other in sorting order. For
> example, this doesn't work:
>
> set v1 'foo';
> set v2 'bar';
> if test $v1 > $v2
> ...
> end
>
> Is there a recommended workaround for this?
>
The POSIX test command doesn't support that and fish has generally avoided
adding incompatible extensions to it. See
http://pubs.opengroup.org/onlinepubs/9699919799/utilities/test.html. The
`test` command is perhaps the only area where fish is a bit too slavish
vis-a-vis POSIX compatibility where everywhere else feeling free to
deliberately not be POSIX compliant. Feel free to open an enhancement
request.
I can't think of a situation where I have needed such a feature in the past
couple of decades. At least not where using another language (e.g., awk,
perl or python) would not have been a better choice. Having said that you
could do this with a simple awk one liner then test the exit status:
function str_lt_str
if test (count $argv) -ne 2
echo str_lt_str: requires exactly two arguments
exit 2
end
awk -v s1=$argv[1] -v s2=$argv[2] 'END { if (s1 < s2) exit 0; exit 1 }'
</dev/null
end
I used awk because there is no guarantee that `command test` implements
this feature. The greater-than case should be obvious.
P.S., Don't forget that `<` and `>` are special characters that perform
redirection. So even if the fish builtin `test` command supported those
operators with strings you would need to escape or quote the symbols.
--
Kurtis Rader
Caretaker of the exceptional canines Junior and Hank
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