How do I change this var ?
max=0;
min=20000000;
cat |while read
do
read a
if [[ $a -gt $max ]]
then
max=a`
fi
`if [[ $a -lt $min ]]
then
min=a
fi
done
echo $max
echo $min
My min and max are still the same, 0 and 2000000. Can anybody help me with this ? I have no idea.
1 Answer
The (main) problem with your script is that setting min and max happens in a subshell, not your main shell. So the changes aren't visible after the pipeline is done.
Another one is that you're calling read twice - this might be intended if you want to skip every other line, but that's a bit unusual.
The last one is that min=a sets min to a, literally. You want to set it to $a.
Using process substitution to get rid of the first problem, removing the (possibly) un-necessary second read, and fixing the assignments, your code should look like:
max=0
min=20000000
while read a
do
if [[ $a -gt $max ]]
then
max=$a
fi
if [[ $a -lt $min ]]
then
min=$a
fi
done < <(cat) # careful with the syntax
echo $max
echo $min
