How to get the biggest number in a file?

Question

I want to get the maximum number in a file, where numbers are integers that can occur in any place of the file.

I thought about doing the following:

Answer 1

I'm sure a C implementation optimized using assembler will be the fastest. Also I could think of a program which separates the file into multiple chunks and maps every chunk onto a single processor core, and afterwards just get's the maximum of nproc remaning numbers.

Just using the existing command line tools, have you tried awk?

time awk '{for(i=1;i<=NF;i++){m=(m<$i)?$i:m}}END{print m}' RS='$' FPAT='-{0,1}[0-9]+' myfile

Looks like it can do the job in ~50% of the time compared to the perl command in the accepted answer:

time perl -MList::Util=max -0777 -nE 'say max /-?\d+/g' myfile
cp myfile myfile2

time awk '{for(i=1;i<=NF;i++){m=(m<$i)?$i:m}}END{print m}' RS='$' FPAT='-{0,1}[0-9]+' myfile2

Gave me:

42342234

real    0m0.360s
user    0m0.340s
sys 0m0.020s
42342234

real    0m0.193s   <-- Good job awk! You are the winner.
user    0m0.185s
sys 0m0.008s