Shell Programming and Scripting

I think my script is working but i am trying to understand while I am tracing to see if it's realli working..

can somebody please comment.. also. is there different way to write this in shell?

sh -x findbiggestnum 1 2 3
+ [ 3 -lt 3 ]
big=0
+ [ 1 ]
big=1
+ [ 2 ]
big=2
+ [ 3 ]
big=3
+ echo 3
3

big=0

for i in $*
do
if [ "$i" > "$big" ]
then
big=$i
else
:
fi
done

can someone please tell me why if i do it below.. it doesn't work?
i put echo 1 2 3 4 5 since I will be getting the list of numbers from another program(just for demonstration) and I want to pipe the results into the script.. but it doesn't work..

echo 1 2 3 4 5 | script

################## script itself ###################
#!/usr/bin/sh

z=0
while read a
do
if [ "$a" -gt "$z" ]
then
z=$a
else
:
fi
done

You are only sending one line to the script; read will read an entire line.

Code:

printf "%s\n" 1 2 3 4 5 | script

Unless there are very few numbers, it will be faster to use sort than a script:

Code:

z=$( sort -n | tail -1 )

sort -n | tail -1 is something I should have thought of... that is perfect solution..
thank you.

however, for my learning solution(as well as any bignners here who are in same boat as I am )..

here was my original script

#!/usr/bin/sh

z=0


grep -i something /dir/somefile |
sed 's/[^=]*=\([0-9]*\) [^ ].*/\1/g' |
while read a
do
if [ "$a" -gt "$z" ]
then
z=$a
else
:
fi
done
echo $z


IF I do aboe script, it does not work...

but if I do

grep -i something /dir/somefile | sed 's/[^=]*=\([0-9]*\) [^ ].*/\1/g' | filename

it works.. ??

sed's output here produces file that looks like

1
2
3
4 already.. so it should work.. but the way i am running through the script, it does not..