[mdlug] UNIX tips: Learn 10 good UNIX usage habits

[Aaron Kulkis]

Robert Citek wrote:
> On Mon, Mar 10, 2008 at 1:54 PM, Aaron Kulkis <akulkis3 at hotpop.com> wrote:
>>  You write a shell script to do some task...
>>
>>  And then someone else writes a shell-script, which has a giant
>>  for loop and calls your script in their script....
>>
>>  It's ridiculous cpu cycle waste...
> 
> Figured I'd try to replicate the authors work
> 
> $ yes and | head -20000000 > tmp/a/longfile.txt
> 
> $ time grep -c and tmp/a/longfile.txt
> 20000000
> 
> real    0m2.142s
> user    0m1.340s
> sys     0m0.036s
> 
> $ time cat tmp/a/longfile.txt | grep -c and
> 20000000
> 
> real    0m1.383s
> user    0m1.344s
> sys     0m0.108s
> 

System time went from 0.036s to 0.108s.
That's a factor of 3.