why invoke anything?  just stay in bash:
>$ cat>/tmp/file<<eoi
>2 | foo | bar
>4 | bar | foo
>1 | bar | foo
>3 | foo | bar
>eoi
>$ mx=;while read -r r;do r=($r);[[ $r -gt $mx
]]&&mx=$r;done</tmp/file;echo mx=$mx
>mx=4
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.mn-linux.org/pipermail/tclug-list/attachments/20151121/8aa6ae9e/attachment.html>